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(Part. III (Tendril-bearing Plants)

(By tendrils, I mean filamentary-thread-like bodies filamentary organs of vegetation, sensitive to contact & capable of movements & moving in consequence & used exclusively for climbing. By this definition, ordinary hooks & rootlets, both of which are used for climbing, are excluded.—

True tendrils are formed by the modification of leaves with their petioles petioles and of leaves with their petioles, of flower-peduncles, perhaps also of branches, & perhaps other organs of and stipules. Mohl, who includes with true tendrils, various other objects organs having a similar external appearance, classes them according to their homological nature, as being modified leaves, flower-peduncles &c. This would be an excellent scheme; but I observe that botanists who are capable of judging are by no means unanimous on the nature of certain tendrils. Consequently I will treat of true tendril describe plant tendril-bearing plants by natural Families, which following Lindley; & this will in most or in all cases keep those of the same homological nature together; but I shall arrange the treat of each Family, one after the other, according to convenience.*

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* As far as I can make out, the history of the discussions our knowledge of tendrils is as follows. We have seen that Palm & von Mohl ha observed about the same time the singular phenomenon of the spontaneous revolving movement of Twining-plants. Palm (s. 58) I presume, observed, likewise, the revolving movement of tendrils; but I do not feel at all sure of this, for he says very little on the subject. Dutrochet fully described this movement of the tendril in the common Pea.—

Mohl first discovered that tendrils were sensitive to a touch contact; but from some cause, which it is difficult to discuss, probably from observing ten too old tendrils, he was not at all aware how sensitive they were & thought that prolonged pressure was necessary to excite movement. Professor Asa Gray, in a paper already quoted, first noticed the extreme sensitiveness & rapidity of the movements of in the tendrils of certain cucurbitaceous plants.—

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(a) The

The species to be described belong to the following ten Families & will be given in the following order:—Bignoniaceæ, Polemoniaceæ, Leguminosæ, Compositæ, Smilaceæ, Fumariaceæ, Cucurbitaceæ, Vitaceæ, Sapindaceæ, Passifloraceæ.)

Bignoniaceæ. This family contains many tendril-bearings, plants & some Twiners & some root-climbers. The tendrils are always modified leaves. The Nine species of Bignonia selected by hazard are here described to show what are remarkable from the diversity of structure & action in their tendrils & form given affording connecting links between these may be in the species of the same genus, and to show how remarkable the action of the tendrils is in some cases.

The species taken together, afford connecting links between twiners, leaf-climbers, & tendril-bearing & root-climbers.) In the description of this species of this genus, & in those of the following Families I shall fully describe certain different peculiarities as fully as I can; in & at the close give a brief summary.

Bignonia (an unnamed species from Kew, closely allied to B. unguis, but with smaller & rather broader leaves). buxifolia. The stem is very thin & flexible.

— A young shoot from a cut-down plant made three revolutions against the sun, at an average rate of 2°. 6'. The stem is very thin & flexible; & when a thin stem vertical stick was placed along-side twined, ascending from left to right, a very slender vertical stick, as well perfectly & as regularly as any any true twining-plant. When thus

[95v]

placed along-side twined, ascending from left to right, a very slender vertical stick, as well perfectly & as regularly as any any true twining-plant. When thus ascending, it makes no use of its tendrils

(Diagram 5.)

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or its petioles; but when it twined round a rather thick stick, & its petioles are were brought into contact with it, these curved round it, showing that they have some degree of irritability. The petioles, also, have exhibit a slight degree of spontaneous movement; for in one case they certainly described very small irregular vertical ellipses. (a) But from From the sensitiveness, though slight, of the petioles & thin shortness, it was very difficult to secure the stem, & to observe their movements both in this & the two following species. The tendrils

(Diagram 5.) [Climbing plants, p. 86]

are so closely similar in all respects to those of the following species, that one description will suffice. When the plant climbs through a thicket of this branch their tendrils are highly serviceable.)

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(a) The tendrils itself apparently curved itself themselves slightly to the same side with the petioles; but speaking loosely the tendril movement was so slight that it may be passed over.

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, which are serviceable only when when the plant passing passes through in the bends of thickets. This singular tendril are so closely similar only rather more slender in all respects to those of the following species, that one description will suffice.

Bignonia unguis. — The young shoots revolve, but less regularly & not so less quickly than with those of those of the last the last species. The stem is scarcely able only to twine round a vertical stick only imperfectly, a turn in one in one one direction taking a whole or half, then ascending for a space straight, & then taking half or a whole turn in another the opposite direction, twined imperfectly, sometimes reversing its direction, round a vertical stick, exactly in the same manner, reversing its direction, as has been described in with so many leaf-climbers; & from the same cause, namely that it is itself a leaf- as well well as climber, though also bearing having tendrils. climber

Each leaf consists of a petiole bearing 1 a pair of opposite leaflets, & between at the point when they thin petioles arise diverge from the main petiole, The and terminating in a tendril, is arises situated which is exactly like that above figured, but a little larger. This is The whole tendril in a young plant is only about half an inch in short, about half an inch in

[in pencil:] It will then

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length in a young plant, & is very unlike most tendrils in shape. It curiously resembles the fo leg & foot of a small bird, with the hind toe cut off. The straight leg or tarsus is longer than the three toes, which rather are of equal length & diverging lie & di like in the same plane: & diverge like the toes of a bird; they The toes terminate in hard & very sharp, hard claws much curved downwards, exactly like the claws on a bird's foot. The tarsus & with the three toes whole tendril apparently represents the main & sub-pet petioles of three leaflets. The main petioles, (but not the petioles of the two lateral leaflets) are is sensitive to the contact of any object; & bend towards it; even a small loop of thread after two days caused one to bend upwards; The, but tarsus & the three toes of the tendril, especially their under surfaces, are likewise sensitive. Hence when the stem a shoot grows through— thicket number of branched twigs, the its revolving movement soon causes bring the tendril with its three hooked claws to catch hold of a into contact with some twig, & then all three toes, (or sometimes one alone), after several hours slowly bend & after several hours seize fast hold of the twigs, exactly like

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a bird when perched. If The tarsus, also, when it comes into contact with a twig, this slowly bends, round quite round, until the whole foot toes are is carried quite round & the toes two of them pass on each side of the tarsus or seize hold of it. If the main main petiole bearing the leaflets comes into contact with a twig or the twig, it this likewise bends round round the twig, until the tendril touches & the seizes hold of the petiole of its own petiole or of that of the opposite leaf which is then seized. When [slip of paper pasted over]

The petioles petioles, & probably even the tendrils in a slight degree apparently move spontaneously, hence when a shoot attempted to twine round an upright stick, both petioles generally come into contact with it, & the contact caused still further bending; so that ultimately both petioles clasped

sensitive to the extreme base, [text pasted over] by which means both petioles much curled sprang from the stem, it sometimes not infrequently happen that both petioles curl roundthe stick in opposite directions, & the foot foot-stalk tendrils seizing on each other or on the their own or opposite petioles, secure fastened the stem to the stick support with remarkable surprising security. so that the speci (a)

This plant seems to me the most efficient climber, which I have examined; & I can believe that it probably could ascent a thin

[98v]

So that this species, differently from the last, uses its tendrils, by the intervention of the spontaneous moving & sensitive petioles, when ascending a very thin vertical stick: both use their tendrils in the same manner when crawling passing through a thicket.

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polished stem, though incessantly tossed by the wind. heavy storms. I may here mention in order. To show how important vigorous health it is for the action of all the parts, that the plant should be in vigorous perfect health, I may mention that when I first examined my a plant, which was growing though not vigorously, I concluded that the tendrils acted only like the hooks on a bramble, & that this was the most feeble & inefficient of all climbers!)

B. buxifolia, the first unnamed species [text pasted over] resemble in all

Bignonia Tweedyana. — This species is closely allied to & behaves in all respects to the two like the last; perhaps it twines rather round a vertical stick rather better. than B. unguis. On the same plant, one branch twined in one direction & another in an opposite direction. The internodes in one shoot case made two circles, each in 2° 33'. I was enabled in this species to observe better than in the other two preceding, the spontaneous movements of the petioles: one made described three small vertical ellipses in the course of eleven

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hours; another moved laterally in an irregular spire. Some little time after the stem has twined round a stick & is securely fastened to it by the clasping petioles & tendrils, it emits at the base of its leaves aerial roots, which curve partly round & adhere to the stick. So that this species of Bignonia combines four different four different methods of climbing, often generally characteristic of different distinct plants, namely twining, leaf-climbing, tendril-climbing, & root-climbing.)

In the foregoing three species, when the foot-like tendrils have has caught an object, they it continues to grow & to thicker, & ultimately they it becomes wonderfully strong, in the same manner as we have seen with the petioles of leaf-climbers.

If the tendril catches nothing, it first slowly bend vertically, vertically downwards, & then its power of clasping is lost. It does not Soon Very soon afterwards it disarticulates itself from the petiole, like a leaf in autumn from the stem, & drops off: I have seen this process of disarticulation in no other cases plants; but in its place uncaught tendrils soon wither away.)

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Bignonia venusta. — The tendrils belong are here considerably modified: The lower part, or tarsus, is four times as long as the three toes; these are instead of lying are of equal length, do not lie in the same plane, bit diverge equally on all sides; their tips are bluntly hooked, so that the whole tendril makes an excellent grapnel.

The tarsus is sensitive on all sides; but the three toes are sensitive only on their outer sides, which correspond with the inferior surface of the feet-like tendrils of the previous species. The sensitiveness is not much developed, for a slight rubbing with a twig did not cause caused the tarsus & or toes to become slightly curved until an hour had elapsed, sus subsequently they straightened themselves. Both the tarsus & toes can catch well seize well hold of sticks. When the stem is secured, the tendrils are seen to spontaneously to sweep large ellipses; the two opposite tendrils move independently of each other. I

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neglected to observe, but have no doubt, from the analogy of the two following allied species, that the petioles also move spontaneously; but these petioles are not irritable like those of B. unguis & Tweedyana. The young internodes also sweep fine large circles, one being completed in 2° 15' & a second in 2° 55'. By these combined movements the grapnel-like tendrils are soon brought into contact with surrounding objects. When a shoot stands near an root upright stick, it twines regularly & spirally round it; as it ascends, it seizes the stick at some little hight above with one of its tendrils, the opposite one hanging down & not being used. The right & left-hand tendrils are alternately used, if the stick be thin, in this manner of ascent; this alternation results follows from the stem necessarily twisting taking one twist on round its own axis for each completed spire.

The tendrils, a short time after catching any object, contract spirally, with the spires

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be curved reversed directions at towards the two ends. Tendrils which have caught nothing slowly bend downwards, but do not contract spirally. With many plants of other genera the tendrils after a long time interval of time contract spirally, whether or not they have caught any object. But this whole subject of the spiral contract of tendrils will be discussed after all thee several tendril-bearing plants have been described.

Bignonia littoralis. — The young young internodes sweep make revolve in fine fine large oval revolutions ellipses: an internode bearing immature tendrils made two revolutions at rate of each in 3° 50'; but when older & the tendrils were mature, the two rate was accelerated revolution was performed at the rate of 2° 44'. But this species, unlike the preceding, is incapable of spirally twining round an round any object: I do not know whether this is due to any want of flexi: this does not appear to be due to

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any want of flexibility in the internodes or to the action of the tendrils, & certainly not to any want of the revolving movement power; nor can I account for the circumstance. Nevertheless the plant can readily ascends excellently well a thin upright stick by the aid of its its two opposite tendrils, bothseizing the stick some way above, & then afterwards spirally contracting.

If the tendrils seize nothing they do not contract. If Big The last species ascended a vertical stick by spirally twining & by seizing it alternately with its two tendrils, like a sailor swarming pulling himself up a rope hand over hand: our present species may be said to partly pulls itself straight up, by putting like a sailor seizing with both hands together to the stick rope above its his head.)

(The tendrils are almost identical in structure with those of the last species. They continue growing for some time, & even afterclasping an object; & when fully grown,

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were nine inches in length, though borne by a young plant. The three divergent toes are shorter relatively to the tarsus than in the former species; they are blunt at their ends tip & but slightly hooked; they are not quite equal in length, one being rather longer than the other. we shall presently see the meaning of these facts. The outer & concave surfaces of the three toes are highly sensitive; for when lightly rubbed with a twig they became perceptibly curved in 4' & greatly curved in 7': in 7° they became straight again & ready to react. The tarsus, for the space of about one inch, close to the toes, is sensitive, but in a rather less degree than the outer surface of the toes, for after a slight rubbing it took about twice as long a time to curve bend. Even the middle part of the tarsus is sensitive to prolonged contact, whilst if acted on soon after the tarsus tendril has arrived at maturity. When the tendril grows old, the sensitiveness irritability sensitiveness is confined to the outer surf toes, & even these m curl round a stick very slowly.

The irritability has little The maturity of the tendril

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is shown by the divergence of the three toes, at which periods their outer surfaces first become sensitive. The irritability has little power of spreading from one part to another; thus when a stick was caught by the part, immediately beneath the three toes, these often remained sticking out & did not clasp the stick.

The tendrils revolve spontaneously. The movement begins before the tendril is mature, wh tendril is converted into a grapnel by the divergence of the toes & before any part has become sensitive; so that the revolving movement at this early period is useless. The movement is at this time slow; two ellipses being completed each together in 12° 9 24° 18'.

As when the tendril was mature an ellipse was performed in 6°; so that even at this period the movement is much more slowly than that of the internodes. Fine large ellipses were swept, but in a vertical & horizontal

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planes by the tendrils. Not only the tendrils, but the petioles bearing them revolved: these petioles, however, are not in the least sensitive. Hence the young internodes, bearing the mature tendrils, the petioles & the tendrils themselves as all in go on all at the same time still go on revolving revolving together, but the different parts at different rates. Moreover the movements of the two opposite petioles & tendrils are quite independent of each other. so that after one tendril has caught

Hence, when the whole shoot is allowed freely to revolve, nothing can be more intricate than the course & rate followed by the extremity of each tendril: a whole wide hemisphere above the tip of the shoot is irregularly searched for some object to be grasped.)

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(One other curious point remains to be mentioned. Some few days after the toes have closely clasped a stick, their blunt extremities f often become, though not invariably, developed into irregular disc-like balls which have the singular power of adhering firmly to the wood. As their cellular outgrowths will be fully described under B. capreolata, I will here say nothing more about them.) The tips of the lea toes apparently showed show some tendency to crawl into dark crevices; but my I was not enabled fully to ascertain this fact, which is certainly characteristic of some of the following species & genera.)

Bignonia æquinoctialis var. Chamberlaynii. — The internodes, long non-sensitive petioles, & tendrils all revolve; & the stem does not twine, but ascends a vertical stick like in the same manner as the last species.

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The tendrils also resemble those of the last species, but are shorter; & the three toes are not quite more unequal in length; two of them being about two-thirds of the length of the third, the & rather thinner; but they vary in these respects.

They terminate are less sensitive to a slight rubbing. They terminate in small hard points, & what is important they do not develop cellular adhesive discs. The I presumed two plants were the same & they differed

The reduced size of th two of the toes seems to indicate & their lessened sensitiveness seem to indicate a tendency to their abortion; & the first-formed tendrils on one of my plants, sometimes had produced only two toes or quite simple tendrils were no toes. &

We are thus naturally led to the two three following species with simple undivided tendrils.)

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Bignonia speciosa. — The shoots revolved irregularly, making narrow ellipses, or spires which represented ellipses or circles, at rates varying from 3° 30' to 4° 40'; for each revolution;but the plant showed no tendency to twine. The Between each pair of leaflets a long simple straight tendril, sometimes more than five inches in length arises, with the tip a little bowed hooked, & blunt. (a) We here first meet with a case, which we shall hereafter find to be very common; namely that the tendril themselves spontaneously revolve like together with the internodes, thus sweeping a larger circuit for some supporting object.— The plant whilst very young &not requiring any support it does not produce tendrils. The simple tendrils of a young plant was five inches in length (a)

The tendrils when rubbed slowly bend to the rubbed side & then subsequently straighten themselves: but they are not very sensitive.

Only after catching any some object they contract spirally.

There is something strange in their action: I repeatedly placed an upright thick & thin, rough & smooth upright sticks it also, rough & smooth, rough & post, end string string string suspended vertically living plants &c near the tendrils them, & these but they these objects were not well seized. The tendrils after clasping an upright stick repeatedly loosed loosed it again; & often often they

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(a)

: they spontaneously revolve, as do probably the short petioles, which are not sensitive.

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would not seize it at all; or and their when they clasped a thin stick, they did their extremities often did not coil closely round it.

(a) Twice I observed there when there was a deep chink in the wood, the point of the tendril were neatly was inserted into it, When, however, their sticks twigs were placed transversely above the plant a shoot they were seized much better; but even in this case they were not always grasped at the first touch; nor did the extremities of the and the middle of a tendril would take a complete turn round a twig, with the terminal part remaining even afterwards stretched straight out, in a manner wholly unlike to that in which any ordinary a tendril of a Leguminous or Cucurbitaceæ plants &c in the above families would behave.)

(The simple undivided tendril terminates ends in an almost straight, sharp, uncoloured point.

The The whole terminal part exhibits one odd habit, which in an animal would be called an instinct; for it continually searches for any little dark hole into which to insert its extremity itself.

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I have observed hundreds of tendrils

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(a) I have observed hundreds of tendrils in f Cucurbitaceous, Passifloraceous & Leguminous plants, & never saw one behave in this manner.

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I had two young plants & after having observed this habit, I gave both of placed near them posts, which either had been bored by beetles or which had become fissured & cracked by drying. & The tendrils by their own movement & that of the internodes, slowly travelled over the surface of the part wood & when the apex came to a hole or fissure it was inserted itself; for la this purpose the terminal half or quarter inch of the tendril was often become bent at right angles to the basal part. I have watched this process between twenty & thirty times. The same tendril would frequently withdraw from one hole & insert its point into a second one. I have seen a tendril remain keep its point, in one case instance for 20° & in another case instance for 36° in a minute hole, & then withdraw it. Whilst the point of the one the of a tendril is thus temporarily fixed inserted, the opposite tendril goes on revolving. The whole length of a tendril fitted adapted

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fits itself closely to the inequalities of the wood; & I have seen one turn at right angles & place itself in a wide & deep fissure, with its apex again rebent abruptly bent & inserted into a little lateral hole. When the After a tendril has clasped a stick, they it contracts spirally; if they it catches nothing they it does not contract. but When it adapts itself They insertion stimulus from fitted adapting themselves to the inequalities of a post, though it has clasped nothing, the stimulus suffices is sufficient to induce the spiral contraction; and this & here comes the odd point, namely that this spiral contraction is in every case ultimately draw the tendril quite away from the post, after they it had fitted themselves itself to the irregularities & had inserted their apica its apex into the some little holes hole or fissure. So that in every case all these nicely adapted movements were absolutely useless, excepting in one single instance, with one single exception the of a single case in which the tip became jammed in a very narrow fissure. I fully expected

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from the analogy of B. capreolata, that the white apex would have develop develop itself into adhesive discs; but I could never see saw even a trace of this process process. Improbable as the view may be, I am led to suspect that formerly the useless harmless, & perhaps in some case still serviceable, habit of the tendril inserting the apex of its tendril its tip into dark holes & crevices, has been inherited by this plant after being having lost either the power of forming adhesive discs or some other useful power.)

Bignonia picta. — This species closely resembles the last in structure, in all its movements & habits, even to grasping repeatedly clasping & loosing the same stick. several times. Perhaps it clasps are thin upright stick rather better than B. speciosa & inserts the apex of the tendril seldomer into little holes & crevices. I casually inspected a fine growing plant of the allied B. Lindleyi, & this apparently behaved in the same manner.

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Bignonia capreolata. — (a) A shoot made three good large revolutions, following the sun, at an average rate of 2° 23'. The stem is thin & flexible, & it made four regular spiral turns round an thin upright stick, (ascending, of course from right to left, & therefore in a reversed direction compared with B. buxifolia) the first described species); but afterwards, from the interference of its the tendrils, it either ascended straight up the stick or in an irregular spire. These tendrils are highly remarkable. in two respects. They arise as before; are were in a young plant about 2 1/2 inches in length & are much branched; the five chief branches apparently they representing two pairs of leaflets & a terminal leaflet one: each of the five branches branch is bifid or more more commonly trifid towards the as its extremity, & with all the points blunt as but distinctly hooked. A tendril when lightly rubbed bends & subsequently becomes straight again; but a loop loop of thread weighing 1/4 of a grain produced no effect. When a The terminal branches of tendril, when a thin stick was placed in contact with them twice became in two cases instances become in 10' slightly curved when touching a stick, and in 10', & so much so in 30' that the tips touched curled round the stick: the basal part of the tendril is less sensitive. The tendrils have

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(a) We now come to a species having tendrils of a different type; but first for the internodes. A young shoot made three large revolutions,

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no true do not spontaneously themselves revolve, or if they move at all move but little; so that they differ much in this respect but are carried for a day or two retaining nearly their some mov position an from the several last described species. They are, however, carried for a day or two round & round by the revolving inter shoots. internodes.)

Then (A remarkable movement now commences, in and the whole tendril slowly curves from the light towards the darkest side of the house. I repeatedly changed the position of the pot & always the successively formed tendrils always pointed to the same darkest spot side. I placed thick post But when I placed a thick post between clo near a a the tendril &, between it & the side light which had whence the light came & which had previously been always avoided, the tendrils pointed this way. In two instances the a pair of leaves stood so that one tendril pointed directly to the light & the other to the darkest side of the house; this latter tendril did not move, but the opposite one bent right over its fellow, so that the t two became parallel both pointing to the dark: I then indirectly turned the pot completely half round; & the crooked tendril which had turned over became straight & the opposite one, which had not previously moved, now turned right over to the dark side.

Lastly in on another plant, three pairs of tendrils

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on the were produced by three shoots at the same time & all happened to be differently directed: I placed the pot in a box open only on one side & I found this obliquely facing towards the light: in a two days all six tendrils, though all bent differently, at different all pointed with unerring truth truly to the darkest corner of the box; though to do this each had to bend in a different manner. Six tattered became flags could not have pointed have pointed more truly from a stream of the wind, than did their branched tendrils from the stream of light, which entered on the one side of the box.─ I then left these tendrils undisturbed for above 24°, & then turned the pot half round, but they tendrils, were now so far fixed & that they could not change their position position direction.) now avoid the light.)

(When a tendril has not succeeded not succeeded, by either through the revolving movement of the interne shoot, or by turning towards any object which intercept the light, in [illeg] getting fastening on a support, it bends vertically downwards & then & then towards the

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stem its own stem, which it clasps together with the supporting stick, if these be one. & thus perhaps aids a little a little aid is thus given in keeping the stem secure. If the tendril seizes nothing, it does not contract contract spirally, but soon withers & drops off. If If it does seize an an object, the main stem & lateral all the branches all contract spirally.)

(I have stated that after the a tendril has come into contact with a stick in about half-an-hour it bends round it; but I repeatedly observed as with B. speciosa & its allies, to my great surprise that it again loosed the stick; & would somehow it repeated this process two or three times. sometimes it seized & loosed the same stick three or four times. After having observed hundreds of tendrils of Cucurbitaceæ, Passifloræ & Leguminosæ plants, I had never saw seen such a circumstance case. Knowing that the tendril avoided the light, I gave them a glass tube blackened within, & a well-blackened zinc-plate, the branches curled round thin tube & bent ab abruptly

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bent themselves over the edges of the zinc plate, but they soon recoiled with what I can only call disgust from their objects & straightened themselves, I then placed near close to a pair of tendrils an extremely rugged rugged a post of with extremely rugged bark; twice the tendrils touched it for an hour or two & twice they withdrew; at last one of the hooked point extremities curled round & firmly seized an excessively minute projecting point of bark, & then to other branches of the tendrils spread themselves out, following with accuracy every inequality of the surface. (a) & the finest process to be immediately described, began in three days.

This process I discovered by having accidentally left a piece of wool near to a tendril I then loosely bound round sticks low, I was thus led to bind loosely a a quantity of flax, moss & wool (its wool must not be dyed, for these tendrils are excessively sensitive to some poisons) round sticks & placed to place these near tendrils, The hooked bent hooked points soon caught the fibres, even loosely floating fibres, & now there was no recoil recoiling; on the contrary the excitement from the fibres, caused the hooks to penetrate the fibres matters & to curl inwards, so that each firmly caught so

[108v]

(a) I then placed near a post without bark close, but deeply much fissured, & the hooked points of the tendrils crawled into all the crevices in a beautiful manner. To my surprise, I observed that the tips of the immature tendrils, with the branches not yet fully diverging, likewise crawled just like roots into the minutest crevices. After the tendrils In two or three days after the tips of the tendrils had thus crawled into the fissures crevices, or after their hooked b ends had seized some projecting point, the final process, now to be described, commenced.)

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either one or two or a small bundle of fibres. The tip tips & the inner concave inner surfaces of the hooks now begin began to swell, & in two or three days can could be seen to be visibly enlarged. After a few more days, it is found the hooks they are were converted into a whitish irregular balls, rather above 1/20th of an inch in diameter, & formed of larger cells than the hooked points of the tendrils itself themselves, coarser cellular matter tissue which is are sometimes wholly enveloped & concealed the hooks by this outgrowth itself themselves. The surface of the cellular balls secretes some viscid resinous matter to which the [illeg] surrounding fibres of the two flax &c adhere. When a one or several excessively fine fibres of the flax or wool have stuck been stuck stick fibre sticks to the surface, the cellular tissue does not grow directly beneath it under them but closely closely on each side; so that when these are several closely adjoining adjoin closely approximate though excessively thin, were fibres, adherent, in many crests caught, so many crests crests of cellular matter, each not as not so thick as a human hair, grew up between them, & these arching over on each both sides grew unite firmlytogether, & these enclosed the several fibres.

As the whole surface of the cellular ball continues to grow, fresh fibres are thus caught adhere & are enveloped; so that I have seen as ball with between 50 & 60 fibres of flax crossing at various angles, & all embedded more or less deeply. Every gradation in the process can could

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be seen, from fibres merely adhering to the surface, to others lying in more or less deep furrows, to others more or less deeply embedded, & or passing through the very centre of the cellular ball. The embedded fibres are so closely clasped that they they a single one cannot be withdrawn.

The cellular outgrowth has such a tendency to unite that I have seen two balls produced from two hooked points grafter grown branches sometimes grow into a single one.)

(a) (I infer that the cellular discs or balls secrete some resinous adhesive matter from the adherence of the fibres to them; but more especially from such fibres this manner loosening of in which the fibres become loosened becoming loose after immersion in sulphuric ether, which likewise, removes small brown glistening points that can generally be seen on the surface of the older balls discs. That as far as I have seen

If the hooked extremities of the tendrils touch nothing, the cellular outgrowth, as far as I have seen, never commences; but curl temporary contract during a moderate

[110v]

(a) (on one occasion, when a tendril had curled round a smooth stick, half-an-inch in diameter, an adhesive ball disc was formed; but generally the tendrils can do nothing with sticks or posts if when smooth. If, however, the tip of any one branch can sec curl round the minutest projecting point the other branches form th discs, especially if they can find any crevices to crawl into. The tendrils quite fails to attach itself to a brick wall.)

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time, will causes a small ball disc to be developed formed. I have seen seven or eight di balls disc developed on the same one tendril. After their development, the now spirally contracted tendrils became woody & very strong; instead of withering & dropping off; one supported nearly seven ounces, & would apparently have supported a much considerably greater weight but to had not the fibres of flax to which the cellular discs were attached been drawn from the supporting stick─ round which they were wound.

This cellular outgrowth & the strengthening of the whole tendril is closely analogous to the enlargement of the cells on the inner side surfaces of the clasped & strengthened petioles of Clematis calycina; but the outgrowth & [illeg]being here confined to a definite points, has a much more remarkable appearance. In another n. american plant. The Virginian creeper or Ampelopsis. The tips of the tendrils became, as is well known, similarly enlarged & adherent.─ From the facts above given I infer that though the tendrils of this Bignonia can can occasionally adhere to smooth cylindrical sticks in & to the back of thick points branches, it is evidently seems yet that they are adapted

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to climb climb thick point trees with their back clothed with (a) lichens, mosses or tillandsia.)

Eccremocarpus scaber (Bignoniaceæ). — Plants kept in my green-house, though growing pretty well, showed no spontaneous movements in the axis stem or tendrils; but when removed to the hot-house, the young shoots revolved at rates varying from 3° 15' to 1° 13': at this latter unusually quick rate one fine large circle was swept, but generally the circles or ellipses were small, & sometimes the movement course pursued was was extremely irregular. The sam An internode, which had revolved made some revolutions, would sometimes stand quite still for 12° or 18° & then recommenced revolving & such strongly marked use interruptions in the movements, I have observed x in so strong well marked a thin hardly any other plant.) (The leaves all consist bear four leaflets, themselves sub-divided, & terminate in a much branched tendril. The medial or main petiole of the leaf, whilst young, moves spontaneously;

[112v]

(a) lichens, mosses, or Polypodium incanum, as I hear from Prof. A. Gray in the cases, in the forests where this Bignonia grows. Finally, it is not a little remarkable, that a leaf should become metamorphosed into an organ which turns from the light, with its tips either crawling like roots into crevices, or sensitive & seizing hold of projecting points, & in both cases finally producing develop forming an cellular outgrowth which secrete an adhesive cement, capable of enveloping the finest fibres & of secreting an adhesive cement.)

(113

petioles move by curving itself, & follows nearly the same irregular course & at about the same rate as with the internodes. As The stem movement to and from the stem is naturally the most conspicuous, & I have seen the chord of a curved petiole forming an angle with of 59° with the stem, & an hour afterwards an angle of 106°. The two opposite petioles do not move together, & I have noticed one is sometimes raised so much as to stand close near to the stem, & whilst the other is greatly not far from horizontal. The basal part of the petiole near the stem moves less than the distal part. The tendrils, besides being carried by the moving petioles, themselves move spontaneously; & those on the opposite sides of the points sometimes move in different tendrils occasionally move in opposite directions. By these various spontaneous several movements of the young internodes, the petioles & tendrils, all acting together, a wider space is swept in search of a support.─)

(The tendrils in young plants are about three inches in length: they bear two lateral & two terminal branches; & each branch, bifurcates twice, with the tips forming a blunt double hooks, having both points directed

[113v]

(a) ; I have seen one leaf of a pair raised so as to be close to the stem, & with the opposite leaf retaining its ordinary moderate inclination.

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to the same side. All the branches of the ten are sensitive on all sides; & after being lightly rubbed, or after coming into contact with a stick, they bend in about 10'. One that was observed & thus become curved at in 10'. after a light rub, took some continued bending for between 3° & 4°; & in 8° or 9° subsequently subsequently became straight again. If the Tendrils catches which have caught nothing, it ultimately contract into an irregular spire, & so it does in one plant see they do & much more quickly, after cla it has clasped clasping a support. Their action in some respect is analogous to that of the tendrils of Bignonia capreolata, but they do not, as a the whole tendril does not move from avoid the light; nor do the hooked tips become developed enlarged into cellular balls. discs.

When they the tendrils came into contact & clasp with with a moderately thick cylindrical stick or with a piece of rugged bark, the several branches of the tendril may be observed slowly to lift themselves up, change their positions, & again come into contact with the support. The object of this movement is that the branches may turn themselves round & so is that all the double hooks, which naturally face in all directions, may come be brought into contact with the wood, (a) The appearance

[114v]

(a) I have watched a tendril which had bent itself abruptly at right angles round the sharp corner of rugged wood rectangular a post, neatly bring every single hook into contact contact with the two surfaces of wood.

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suggested the belief, that though the whole tendril is not sensitive to light, yet that the tips are so, & that they turn & twist themselves towards the any opake opake surface. Ultimately the branches arrange & fit themselves most neatly very neatly to all the irregularities of the most rugged bark, so that they resemble f in their irregular moves courses a river with its branches, as engraved engraved on a map. But when a tendril has thus arranged itself round a rather thick smooth cylin stick, the subsequent spiral contraction often generally spoils the neat arrangement all & draws the tendril from its support. So it is, but in a less degree not quite in so marked a manner, when a tendril has spread over flat rugged bark; but for in this case the spiral contraction will often firmly draw of opposite branches often sometimes draws two two the opposed hooks firmly to their supports. (a) When a tendril has curled round a stick is caught so thin a stick that the is caught, that the tips of the tendril canwind round & seize its own wind round the lower basal parts, lower stems on itself, branches its own branches, it is not perfectly, but not neatly secured. The extremities of all the several branches of the tendrils, close to the little double hooks, have a strong tendency to curl completely inwards, & are excited by do to this by contact

[115v]

(a) Hence we may conclude that these tendrils are f not increa perfectly adapted to seize smooth & moderately thick thick sticks, or rugged bark.─ When so thin a thin stick or twig is caught, the extremities tips of the placed near a tendril, the its terminal branches wind round & seize th its own lower branches or main stem, & the stick is then firmly perfectly, but not neatly, seized. grasped.

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with the thinnest objects. This accounts for the tendrils apparently preferring such objects, as the excessively thin columns of as the same a long grass or exotic grasses, the long flexible bristles of a brush or the very thin rigid leaves of a species of Asparagus, all of which objects they seized in an really elegant admirable manner; for the tips of each subbranch seized one, or two or three of for instance the bristles, for instance, & then the spiral contraction of the branches bro several branches brought all their little parcels close together, so that thirty or forty bristles, as it were, were sized tied together into a one bundle bundle foregoing at , & thus afforded an excellent an perfect excellent support.─

Polemoniaceæ — Cobæa scandens: — this is an excellently admirably constructed climber. The terminal portion of the petiole, which has been modified converted into a a the tendril, is about five was in one very fine specimen, eleven inches in length, & the basal part, which bore two pairs of leaflets, was only two & a half inches in length. The tendril revolves more rapidly & vigorously than in any other plant observed by me, with the exception of one Passiflora. It

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vigorously revolve than any other seen by me. It made three fine large, nearly circular sweeps, against the sun each in 1° 15', & two other circles in 1° 20' and 1° 23'.

Sometimes it travels much inclined position or has & sometimes nearly upright. The longer, straight tapering stem of the tendril bears alternate branches, & basal portion moves lower part moves but little, & the basal portion, or petiole, which bears leaflet not at all; nor do the internodes move revolve; so that here we have the tendril moving by itself; with Bignonia capreolata unguis the internodes alone moved; & with most of the other species of Bignonia & with the B. littoralis & the Eccremocarpus the internodes, tendrils & petioles all revolved. The long straight tapering main stem of the tendril bears alternate branches; & each branch is several times several repeatedly divided, with the finer divisions branches as thin as very thin bristles, yet strong, extremely flexible, yet string & highly elastic, so that they are blown about by a breath of air. The extremity of each branchlet is a little flattened, & terminates in a minute double (sometimes single) hook, formed of a hard, brittle translucent, woody substance, and as sharp

(118

(Tendrils)

as the sharpest the finest needle. (a) I counted 36 of them double hooks on one tendril. They seem so sharp readily as to catch soft wood wood, or the skin of the hard or get much entangled into grass. Excepting these hardened hooks & excepting the thick basal part of the central stem of the tendril, every part of every branch is highly sensitive on all sides to a slight touch, & in a few minutes bends to the touched side. By lightly rubbing various several branches on different & opposite sides, the whole tendril rapidly assumed an extraordinarily crooked shape: these movements from contact I ma do not interfere with the ordinary revolving movement. The branches after becoming greatly curved, straightened themselves at a quicker rate than in any other plant case tendril seen by me, namely in between half & a whole hour. After the tendril has caught any object, the spiral contraction likewise came as in also begins after an unusually short interval of time, namely in about twelve hours.─

[118v]

(a) In large tendrils, the hooks are sometimes single. In on the eleven-inch tendril, I counted 94 of these beautifully constructed little hooks. They readily

(119

(Tendrils)

(Just before the tendril is mature, the terminal branchlets cohere cohere, & the hooks are curled closely inwards; at this period no part is sensitive to a touch; but as soon as all the branches diverged have diverged & the hooks stand out, full sensitiveness is acquired. It is a singular circumstance that immature & a tendril, becoming sensitive, begins to revolve at at for a short period its full velocity; this movement must be quite useless as the tendril in this state can catch nothing: it is a rare instance of a want, though only for a short time, of perfect co adaptation in the structure & functions of a climbing plant.

At the period when the tendril is probably matured the leaflets at its base are quite young & small petiole, bearing with it's

The petiole with the tendril, perfectly matured, but with the leaflets still young & small, stands at this period vertically upwards; with the top of summit of the young growing shoot or axis being thrown to one side. Consequently

The tendril, whatever prolonged petiole stands vertically up & being thus standing vertically up sweeps a circle right above the stem below of a plant, & is thus well adapted

(119

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(In accordance with the rapidity of all the movements of the tendrils, their direction in shoot: in the

(120

(Tendrils)

to catch some objects above, & aid to favour the ascent of the plant. The leaf can with its tendrils after a short time bends to one side downwards, down, allowing the next succeeding leaf with its tendril to become vertical, & ultimately becomes it assumes a horizontal position; but long before this has occurred, the tendril, supposing it to have caught nothing, has lost its powers of movement & some has spirally contracted into an entangled mass.

In accordance with the rapidity of all the movements of the tendrils their direction is short: in a plant growing vigorously from being placed in the hothouse, a tendril revolved, but counting only from the period when it became sensitive, during only about only about 36 hours but during this period it probably made at least 27 revolutions.)

When a thin stick is put into the path of (When the branches of a revolving tendril strike against a twig thin stick, it quickly bends twig, the contact causes these branches it's a stick, they quickly to bend round & clasp it; round it, and they become firmly secured; but the little hooks

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play an important part, especially if a terminal the end only the extremity of the tendril catches is caught, in retaining preventing its it, being too quickly dragged away by the its own rapid the revolving movement too quickly for its irritability to act. As soon as a tendril has caught bent round either a smooth stick, or a thick rugged post, or even flat smooth has come into contact with planed wood (for it can at least temporarily adhere even to so smooth a surface as this) The same peculiar movement commences begins in the several branchlets of the tendril, as has been described in those of the Bignonia capreolata & the Eccremocarpus; namely the branchlets, lift themselves up, then one after the other lifts themselves up themselves, itself up however which have thin hooks already downwards up remaining [illeg] & securing the tendril, whilst the others twist about till they bring its arrange itself themselves in conformity with every inequality of the surface & bring its their hooks, which, originally facing to all sides, in various directions, down into contact with the wood. (a) It was quite a pretty sight to (The perfect manner in which the branches of the tendrils thus arranged themselves, creeping like rootlets over all the inequalities & into any deep crevice, was quite a pretty sight; for it was even perhaps more perfectly effectual effectually done than is by the tendrils of the former species, & was anyhow more conspicuous, as the upper

[121v]

a) The use of the hooks was shown by giving the tendrils tubes & slips of glass to catch; for these, though temporarily seized, were invariably loosed lost, either during the arrangement of the branches the spiral contraction ensued.)

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surfaces of every the main stem & of every division of the tendril branch to the extreme hooks is angular & coloured green, & whilst the lower surfaces are rounded & purple. I was led to infer, as in the former cases, the light guided these their arrangement conformity conforming movements of the branches of the tendrils; I made many trials with blackened black & white stem glass & card to prove it, but failed from various causes; yet these trials countenanced the belief. The tendril of the may be looked at as a much divided greatly leaf split into filaments with the segments facing in all directions; hence when irritated is their revolving movement is arrested, would so that the light shining on it shines on them steadily in one direction, than would be is nothing surprising in all their be upper surface of all the segments facing turning toward the light; & this may aid the movement but will not suffice account for its movement; for the segments could besides facing more not only turn round round to, but would move towards the light, whereas in fact the under surfaces, which face the hooks, whereas, the segments move towards the dark; as well as turn round & face to it; whereas in truth the segments, or branches of the tendrils, not only turn their upper surface to the light & their lower surface, which bear the hooks, to the dark, or to any closely adjoining opake object, this is to the dark; but they

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(Tendrils)

moves actually curve or bend from the light towards it. towards the dark. in the same

(With plants growing naturally When the Cobæa grows in to open air, the wind must aid the tendrils extremely flexible tendrils in catching seizing on a support; for I found a mere breath from a sufficed to cause a the extreme branches of a tendril to hooks on a plant catch by its hooks twigs, which it they could not which by it's the revolving movements. It might have been thought that a tendril thus hooked only by its extremity alone would then remains & could not have firmly become grappled with fairly grasped its support. I saw But I watched several times I watched cases like the following, one of which one alone alone I will give describe: a tendril caught a thin stick by the hooks of one of its two extreme branches; though thus held by the tip, it continued to try to revolve, bowing itself out successively all round to all sides & thus moving its branches: soon, the other extreme branch soon caught the stick, the first branch then loosed itself hold, so as to aid arranged itself hooks better & then caught hold again. After a time, from the continued movement of the tendril, a third

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(Tendrils)

branch caught by a single extreme bark; no other branches as any could, are,as the things then remained, could could possibly have touched the stick; but before long the main stem towards its extremity, began just perceptibly to contract & curve itself into an open spire & then to shorten itself, (b) & as it continued to try to revolve, a fourth branch was brought into contact, & As the spiral (a) contraction continued, progressed in the main stem & in the branches, all of the lower branches, one by one after another were clasped one brought interacted neatly with the branch of the tendril seized the stick, & some or arranged the hooks & other the stick & either clasped it their other on their own branches; wound round it & seized other branches of the tendril; until the whole tendril was tied together round the stick in a inextricable knot. The

clasped branches, though before at first so flexible now became still after a time became rigid, & even much stronger than they were before at first. And Thus the plant is secured to its support in an admirable manner.)

[124v]

(b) (dragging the whole shoot towards the support stick)

[124vv]

(a) contraction progressed both in travelled downwards along the main stem & by the branches, all the lower branches, one after another, were brought into contact with the stick, & wound round it & round their own branches, until the whole tendril was tied together in an inextricable know round the stick. The

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(Tendrils)

Leguminosæ.─ Pisum sativum. — This plant has been The common pea was the subject of the a valuable memoir by Dutrochet* who discovered that the internodes & tendrils revolve in ellipses. The ellipses are generally very narrow, but sometimes approaching approach to circles. I rep several times observed that the longer longer axis of the ellipse slowly changed its direction, which is of importance, as the tendril is thus slowly made to sweep the whole circumference a wider circuit. Owing to this change of direction & likewise to the movement of the whole plant stem towards the light, the successive irregular ellipses so often form a still more irregular spire. I have thought it worth while here to annex a tracing of the course pursued by the upper internode (Diagram 6.) [Climbing plants, p. 113] (the movement of the tendril being neglected) of a young plant from 8° 40' A.m. to 9° 15' P.m. The course was traced first on a hemispherical glass placed over the plant, & the dots with figures give the hours of observation; each dot being joined by a straight line; no doubt these lines of the course had observed at shorter intervals, were it

[125v]

* Comptes Rendus Tom. 17. 1843, p. 989.

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would have been all curcilinear. The tip extremity of the petiole, when the young tendril aros arises, was two inches from the glass so that is a pencil two inches long had been were had were been in imagination affixed affixed to the petiole, it would have traced have traced the annexed figures on the under side of the glass; but it must be remembered that the figure is here reduced to one half (Here insert woodcut)

But As a full-grown (a) as the tendril is longer than two inches & as it bends itself moves & revolves in harmony with the internode, a considerably wider space than that here figured specified (& so represented one-half reduced) is swept. by the it. Dutrochet observed (p. 994) an ellipse completed in 1° 20; the I I saw one completed in 1° 30'. The course forward direction followed is variable, either with or against the sun.)

(Dutrochet asserts that the petiole of the leaf spontaneously moves, as well as the young internodes & the tendrils; but he does not say that he secured the internodes, & when this was done done, I could never detect any movement in the petiole, except to & from the light.)

(The tendrils, on the other hand, when the internodes & petioles are secured, make zig irregular spires or regular ellipses exactly like those described made by the

[126v]

neglecting the first great sweep towards the window light from the or window, the extremity end of the petiole swept a space four inches across in one direction, & three inches in another. As a full-grown tendril is considerably above two inches in length, and as the tendril itself bends & revolves in harmony with the

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internodes. A tendril only 1 1/8 inch in length, moved revolved. Dutrochet has shown that the when a plant is placed in a room, so that the light enters laterally, the internodes travel much semi-circle the internodes move mov travel much slower from quicker to the light than towards it from it: on the other hand, he asserts that the tendril itself curves from the light towards the dark ro side of the room. With much deference to this great observer, I think he was mistaken owing to his not having secured the internodes. I took a young plant with highly sensitive tendrils, & tied the petiole so that the tendril alone could move; it completed a perfect ellipse in 1° 30' & I then turned the plant half round, but the there was no difference it so that the opposite side faced the light, but this caused no change in the next succeeding curvature in movement of the tendril.

The next day I watched a plant similarly secured until the the tendril (which was highly sensitive) made an ellipse in a line exactly to and from the light; the movement was so great

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(Tendrils)

that the tendril becomes horizontal bent curved itself down down at the two ends of the ellipse its elliptical course, into rather a little beneath the horizon, thus travelling more than 180 degrees; but the ending down curvature was fully as great towards the li light as towards the dark side of the room.─ I believe Dutrochet was misled by not securing the internodes & by observing a plant of which from the quite unequal age of the internodes and tendrils, from inequality of age, had come not to no longer curved or wound in harmony together.)

Dutrochet made no observations on the sensitiveness of the tendrils; these, whilst very young and being only about an inch in length with the leaflets on the same petiole only partially expanded, are highly sensitive; a single light touch with a twig on the inferior or concave surface near the tip caused them quickly to bend, as did occasionally a loop of thread weighing 1/7 of a grain. The con upper or convex surface is not barely or not at all sensitive. After bending from a touch the tendrils straightened itself in about two hours & was ready to act again. As soon as the then

 

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(Tendrils)

tendrils begin to grow old their tips extremities become hooked, & a large tendril bearing thin fine large one with the lateral pair of lateral pair of branches on each side appears at the period a fine grappling instrument & would naturally be thought to be thin in perfection. and at this period are bearing their pairs of & they then appear, with their two or three pairs of [branches], are branches appears a fine grappling instrument admirably fitted for its work admirable grappling instrument; but this is not the case, for at this period the tips have wholly or nearly lost their sensitiveness; some were not all all acted on when when hooked on to twigs some were not at all acted on affected, & others required from 18° to 24° to clasp the twigs; Ultimately the lateral lateral branches of the tendrils, but not the main middle or main stems of the tendrils, contract spirally.)

Lathyrus aphaca. — as the tendril here replaces the whole leaf (except occasionally in very young plants); the leaf itself being replaced in function by the large stipules, it might have been expected that the tendrils would have been highly developed; this, however, is not so. the case. They are moderately long, thin, sh & unbranched,

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(Tendrils)

with their tips slightly curved; they are sensitive, whilst young on all sides, but chiefly on the concave side of the extremity. They exhibited have no spontaneous revolving movement power; but are at first they are inclined upwards at an angle of about 45° with the horizon; then become move into a horizontal position, & ultimately bend downwards. The young internodes, on the other hand revolve in ellipses, & carry with them the sensitive tendrils. Two ellipses were completed each in about nearly 5°; their longer axes, as with the pea, of their two & of some subsequently formed ellipses were directed at about an angle of 45° to the line of the axis of the previous ellipse.) whole: so that axis.

Lathyrus grandiflorus. — My p The plants observed were young & not growing very vigorously, yet sufficiently, I think, for my observations to be trusted. Here we have the rare case of neither internodes nor tendrils having any spontaneous revolving power. The tendrils in vigorous plants are of large size, & of the twice above four inches in length & are often twice divided twice over into three branches; the tips are curved & sensitive on their concave sides; the basal lower

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part of the middle central stem is hardly at all sensitive. Hence this plant climbs simply by its tendrils being brought, by the growth of the stem or more efficiently by the wind, into contact with surrounding objects, which they then well effectually clasped. I may add that neither the tendrils or the internodes or both of Vicia sativa spontaneously revolve.

Compositæ - Mutisia clematis. — The enormous family of the Compositæ is well known to include very few climbing plants. We have seen in the Table in the first part that Mikania is a regular twiner, & Mutisia is the only genus in the family, as far as I know can learn, which bears tendrils: it is therefore interesting to discover that these tendrils, though rather less metamorphosed from their primordial be foliar nature than most other tendrils, yet display all

(131A

(Tendrils)

the characteristic spontaneous movements, both spontaneous & when excited by contact.)

(The long leaf is of considerable bears seven or eight alternate leaflets & terminates in a tendril which, in a plant of considerable size, was five inches in length. It consists generally of three sometimes branches; which evidently represent the petioles & midribs of three leaflets [illeg], much elongated; for these branches are square on the upper surface, furrowed, & pale-coloured in the middle edged with green, exactly like the petiole & midribs. Moreover in the a plant whilst quite young, the green edging of to tendrils, sometimes expanded into a narrow laminæ or blades. Each branch is arched curved a little downwards, & slightly hooked at the extremity.)

The young upper young internode revolved, judging from three ellipses revolutions, at an average rate of 1° 38'; (a) the plant apparently cannot twine. The long petioles & the tendrils itself, both together & separately, are are in constant

[131Av]

(a)

; it swept long ellipses, with (a) in the longer axes of the ellipses were directed at right angles to each other;

(131B

(Tendrils)

slight movement. But the movement is slower & much less regularly elliptical than that of the internodes: it is apparently much affected by the light, for the whole leaf sinks usually sank during the night & rises rose during the day, moving in a marked course to the west. The tips of the tendrils are highly sensitive on their lower surfaces; one just touched with a twig became perceptibly curved downwards in 3' & another in 5'; the upper surface is not all all sensitive; the sides are slightly moderately sensitive, so that two branches rubbed in their inner sides converged & crossed each other. The petiole of the leaf & the lower parts of the tendril, half-way between the upper leaflet & the lowest tendril branch are not sensitive. A tendril after curling from a touch became straight again in about 6° & was ready to react; but one that had been so roughly touched rubbed as to coil into a close helix was not quite probably straight after 13°. The tendrils retain their sensibility from to an unusual age; for

(131C

(Tendrils)

one borne by a leaf, with five or six fully developed leaves above above, was still active. If a tendril catches nothing the tips, after a considerable interval spontaneously curl into a a small open helix; when they have clasped an object, they contract spirally, with reversed spires.)

Smilaceæ. — Smilax aspera, var. maculata. — Aug. St.-Hilaire* (a) considers that the tendrils which arise from the petiole near the axis stem, as a modified pair of lateral leaflets; but Mohl (s. 41) ranks them without doubt as modified stipules.─; & if one making transverse motions of the petiole between the point at which they the tendrils appear to arise & the axis, it can be clearly seen that they are independent of the petiole. Here then we have a new organs though related in its their nature to a leaf leaves, modified into ten a new tendrils. The These tendrils are from are at one inch 1 1/2 to 1 3/4 long, in length, are then pointed & slightly curved towards their of an inch in length, are thin, & have slightly curved, pointed

[131Cv]

* (a) Leçons de Botanique &c. 1841, p. 170.─

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extremities. They diverge a little from each other & stand at first upright, nearly parallel to the axis stem

(Woodcut. 7.) [Climbing plants, Fig. 7, p. 119]

When lightly rubbed on either side, they very slowly bend to that side & ultimately subsequently become straight again. or are

48 [part of the text pasted over] touching the concave side of

The back or convex side of a tendril placed in contact with a stick became just perceptibly curved in 1° 20', but did not completely surround it the stick till 48° had elapsed; the concave side of another tendril is curled with fairly clasped a stick in 5° & was already considerably curved in 2°.─ As the tendrils grows grow old, it they diverge from basal each other still more and slowly bend slowly move towards the stem & then downwards, so that it they project on the opposite side of the stem to that on which it arises, it they arise; they still retain its their sensitiveness, & can clasp a stick placed behind the stem.

(a) Ultimately the two tendrils belonging to the same petiole, if they do not come

[132v]

(a) Hence the

[132vv]

(a) Owing to this movement the plant, though the leaves are placed alternately on the stem can ascend a thin upright stick, & can clasping it with the tendrils which arise from the leaves placed alternately on opposite sides of the stem.

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(Tendrils Smilax)

into contact with any support, only cross each other (as at B. in Fig. 7)─ behind the stem & loosely clasp it. their one stem of the plant. They (a) do not contract spirally in any case.

Their chance of finding a support, depends entirely on the growth of the plant, on the wind, & & on their own their own slow backward & downward (B) movement, of the tendril give aided probably by the action of the light; for neither the internodes nor the tendrils have any spontaneous proper revolving movement.─ From this latter circumstance, fact, from the slowness of the movement of the slow movement of the tendrils after after contact. (though on the other their its their sensitiveness is retained for an remarkable unusual length of time), from their shortness & their single structure & shortness, this plant is the least shows less skill & in energy perfection in the means of climbing than any other tendril-bearing plants observed by me.─ Whilst very young & only a few inches in height it does not produce any tendrils; & considering that it does not grows to any great height only about eight feet high, that the stem is zig-zag & is furnished, as well as the petioles, with spires. it is surprising, that it should not climb like our bramble it should be provided with tendrils comparatively inefficient though they be.

[133v]

B/ movement, which is probably guided to a certain extent by the movement from the light or towards any dark object;

[133vv]

(a) This movement of the tendrils towards & round the adjoining stem is to a certain extent guided by the action of the light; for when a plant was so placed, that one of the two tendrils in their slowly moving had to travel towards the light & the other from the light, the latter always travelled to more quickly than its fellow. The tendrils Hence their grow This avoidance of the light or quick movements to the dark would probably guide the tendril in finding a support.

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(Tendrils Smilax)

in these are, & that It has not might have been left, one would think, here thought, to climb by the aid of its spires alone, like our brambles. But then it belongs to a genus, some of the species of which are furnished with five much longer tendrils; & we may believe that S. aspera is endowed with these organs some exclusi owes its poor tendrils to relationship one solely from being descended from progenitors descent from more [2 words illeg] more highly organised as climbers organised in this respect.) organised as far as climbing is concerned. more highly organised in this respect.)

Fumariaceæ — Corydalis claviculata. — According to Mohl (s. 43), both the outer leaves & the extremities of the branches are converted into tendrils. In the plants specimens examined by me all the tendrils were certainly foliar in their nature, & it is a surprising fact that the same plant should produce tendrils of such widely different homological nature. Nevertheless, from From this statement, however, by Mohl, I have placed ranked this Corydalis amongst the true tendril-bearers; if classed exclusively

(134A

(Corydalis)

by its foliar tendrils, it would be very doubtful whether it ought not to have been placed ranked amongst the leaf-climbers, together with its allies Fumaria & Adlumia. For the majority of its so-called tendrils still bear leaflets, though excessively reduced in size; with only a few some few branches existing as true tendrils, completely destitute of leaflets laminæ or blades. Hence we here see catch a plant at the exact stage in the actual state of transition from a leaf-climber to a tendril-bearer, so that this plant is very interesting for.

(a) I have seen plainly examined specimens from one locality alone namely Hangline; & it is not improbable that plants growing in other under different condition might have all their leaves a little more or less m changed into true tendrils.

When the plant first rises from the ground, the leaves are not modified; but some the leav next-formed leaves have thin terminal leaflets reduced in size, & soon all the leaves assume the structure, which is here represented of the natural size. This (Woodcut 8.) leaf have nine leaflets, the lower ones

[134Av]

(a) Whilst the plant is young, only the outer leaves, are partially converted, but when full-grown all the leaves, are for have their extremities more or less modified perfectly converted into tendrils.

(134B

(Corydalis)

most much sub-divided. The terminal part of the petiole above the leaflet (f), was is elongated one and a half inch in length, & is more elongated & thinner than the other lower parts of the petiole; & this portion, one inch & a half in length may be considered as the tendril. The leaflet borne by this it part are greatly reduced in size, varying from being on a average less than about the tenth of an inch in size length & very narrow; one very small one measure 1/12th of an inch in length & 1/75th in breadth; another so that they are almost microscopically minute; yet they still have branching nerves & are still true leaflets, terminating in a little spire like ordinary leaflets. But This breadth gradually diminishes, until some, (as a and d in the figure) have no trace of a lamina or blade. Occasionally all the terminal leaflets are in the latter condition, & we then have a true tendril.

The attenuated several terminal petioles, bearing the reduced leaflets (a, b, c, d) are highly sensitive; for a loop of thread, weighing only the 1/16th of a grain caused any part them in in under 4° to to become greatly curved; when the loop

(134C

(Corydalis)

was removed, the petioles straightened themselves in about the same time. The petiole e was rather less sensitive; & in another specimen, in which the corresponding petiole bore rather larger leaflets, a loop of thread weighing 1/8' of a grain did not cause curvature until 18° had elapsed. Loops of thread weighing 1/4th of a grain, left suspended on all the the lower petioles (f to l) during several days, produced no effect. Yet when they the petioles f, g, & h were not quite insensible, for when left in contact with a stick for a day or two, they slowly curled round it. The young So that the sensibility gradually diminishes from the tendril-like extremity to the base.

The young internodes are not at all sensitive, which makes Mohl's statement that they are converted into tendrils the more surprising, not to say improbable.)

(The leaf whilst young & sensitive, stands almost vertically upwards, as we have seen in the case with many tendrils. It is The whole leaf is in

(134D

(Tendrils Corydalis)

continual movement. One that I observed swept fine large, though irregular, ellipses, sometimes narrow, sometimes broad, with their longer axes at in directed to different directions at an average rate of about 2° for each revolution. The young internode, bearing the leaf likewise revolved irregularly in ellipses or spires; so that by these combined movements a wide considerable space is was swept for a support. If the terminal & attenuated portion of a petiole seizes nothing, it spontaneously bends downwards & inwards, as do so many tendrils; & than soon afterwards has lost loses all irritability & spontaneous movement. This bending down is of a very different nature from that which occurs with the ends of the leaves of now several many species of Clematis; for their leaves, when thus hooked acquire their full sensitiveness, & as this is is lost, they became bend up & became straight; whereas with Corydalis, exactly the reverse occurs.

(135

(Tendrils Dicentra)

Dicentra thalictrifolia. — In this allied plant, the metamorphosis has been complete & the terminal leaflet are converted into perfect tendrils. Whilst the plant was young, the tendrils appeared to be like a modified branches, so that a distinguished botanist thought this was their nature; but in a full-grown plant there can be no doubt, as I am assured by Dr. Hooker, that the tendrils are modified leaves. The tendrils, when of full size are above five inches in length; they bifurcate twice, thrice, thrice or even four times; their extremities are their tips are of the branches are hooked but blunt. All the branches of the tendrils are sensitive on all sides, but the basal portion of the main stem is only slightly so sensitive. When The terminal branches when lightly rubbed with a twig they do did not curve quickly, not until 30 from30' to 42' had had elapsed: they slowly became straight again in between 10° and 20°. ─ A loop of rather thread, weighing 1/8th of a grain plainly caused the thinner branches to bend curve; as did occasionally a loop weighing 1/16th of a grain but this slight weight, though permanent retained left- suspended was not sufficient to cause a permanent flexure.─ Both The whole leaf leaf & the supporting internode bearing leaves & the with its tendrils which is the itself themselves both together & the young upper internode both revolve together vigorously & quickly though irregularly, & sweep a wide space. The figure traced on the a

(136

(Tendrils Corydalis)

bell-glass, owing to the spontaneous rising & falling of the whole stem, was was either an irregular spire or a zig-zag line. The nearest shape approach to an ellipse was an elongated figure if 8 with one round a little open; this was completed in 1° 53': during a period of 6° 17', another shoot made a angular figure apparently representing three & a half ellipses. When the internodes leaf bearing the lower part of the petiole bearing the leaflet was securely fastened, the tendril itself described similar but much smaller figures.) now less than three internodes beneath the uppermost leaf all revolved, reversing harmoniously with the curving self-bending tendril

(This species climbs well. in the midrib The tendrils after clasping quickly thicken become thicker & more rigid; but the blunt hooks do not turn turn themselves to the supporting surface, in the admirable manner inter crossed to be seen in some of the species of Bignoniaceæ & in the Cobæa. In After some days after the tendrils have clasped any object the main stem does not spirally contract

(137

(Tendrils corydalis)

Cobæa. In young plants, two or three feet in height, with the tendrils which are only half the length of those borne by tall the plants when grown taller those often clasping a support, do not contract spirally, but became only slightly flexuous. Full-sized tendrils, on the other hand, contract spirally, excepting the thick basal stem portion. Tendrils which have caught nothing, simply bend downwards & inwards, like the extremities of the leaves of the Corydalis claviculata.)

(137

[page crossed]

(Tendrils corydalis)

but it became slightly flexuous, & thus shortens itself a little, giving the first indication of the process of spiral contraction. If the tendrils catch nothing, they simply bend downwards & double then became doubled inwards.

(138

(Tendrils Cucurb:)

Cucurbitaceæ.─ The tendrils in this order Family have been ranked by several competent judges as modified leaves, stipules, & branches; or the same tendril as part leaf & part branch. Decandolle considers the tendrils differ in two of the Tribes as* of different in their homological nature* (a) From these doubts on the nature of the tendrils. I have placed the Family in its present position.

From facts recently adduced by Mr. Berkeley thinks that Payer's view is thought seem is the most probable, namely, that the tendril is "a separate portion of the leaf itself;" * (b)

Echinocystis lobata. — I made an immense a great number of numerous observations on this plant (raised from seed sent me by Prof. Asa Gray), for I first observed in this it the spontaneous revolving movements of the internodes & of the tendrils, and knowing nothing on the subject was infinitely perplexed by the of the natures of their movements, was infinitely perplexed by the whole case of the false false appearance of the a twisting of the axis. without any real twisting of, as shown by little paper names attached to

My observations many be now now be greatly condensed. I recorded the times of thirty-five revolutions of the internode & tendrils thirty-five times: the longest times slowest rate

[138v]

* (b) Gardeners Chronicle 1864. p. 721.

[From the affinity of the Cucurbitaceæ to the Passifloraceæ, it might be argued that the tendrils of the former are modified flower-peduncles, as is certainly the case with those of Passion-flowers. Mr. R. Holland (Hardwicke's 'Science-Gossip,' 1865, p. 105) states that "a cucumber grew, a few years ago in my own garden, where one of the short prickles upon the fruit had grown out into a long, curled tendril."]

[138vv]

* (a) I am indebted to Prof. Oliver for information on this head. In the Bulletin de la Soc. Bot. de France 1857, there are numerous discussions on the nature of the Tendrils in this Family.

(139

(Tendrils Cucurb:)

was 2°, & the average, with no great fluctuations, was 1° 40' for each revolution. Sometimes I tied the internodes, so that the tendrils alone curled moved; at other times I cut off the tendrils whilst very young, so that the internodes moved revolved by themselves; but the average rate of movement was was not thus affected. The mo course generally pursued was with the sun, but often in an opposite direction; sometimes the movement would stop for a short time, during a short time would either stop or be reversed; for a short period: then changes seem and this generally to even take place occurred when the plant being placed near a window the internode faced the light. (a)

The two uppermost young internodes alone alone revolve; move moved; as the lower of the two grew grows old, only its upper part alone moves moved revolved. The summit of the shoot upper internode made an ellipse or circle about three inches in diameter; whilst the sum tip of the long tendril swept a circle 15 or 16 inches in diameter. During the revol revolving movement, the internodes became curled curved to successive points of the compass; & were in fact would be in often in

[139v]

(a) I have observed In one instance an old tendril, which had nearly ceased revolving, many moved in one direction & which the young tendril above moving moved in the opposite direction.─

(140

(Tendrils Cucurb:)

one part of this course they were inclined at about 45° or 50' to the horizon, & in another part stood would stand be vertical.

There was something in the appearance of the revolving shoot internodes which continually gave the false impression that their movement of the internodes was due to the weight of the long & spontaneously moving revolving tendril; but in suddenly cutting off the tendril with a sharp scissors, the top of the shoot rose very little & went on revolving: this false appearance I believe is apparently according due to the internodes & tendrils all curving curving & moving harmoniously together.─)

(When the internodes were secured, the tip of the tendril made revolved of course in a smaller b course; but likewise tendril described a much narrower ellipse that when the internode revolved; & if not carefully observed seemed to move laterally merely to & fro in the same line; strictly strictly speaking the course was generally a longitudinal segment of an ellipse. The cause of this was evident; the tendril forms an acute angle, with the young shoot above; & this

(141

(Tendrils Cucurb:)

(I repeatedly saw, & always with interest, that the revolving tendril as it revolved, when though inclined during the greater part of its course at about an angle of about 45° (in one case of only 37°) above the horizon, which in one part of its course stiffened & straightened itself from tip to base & became nearly or quite vertical. This occurred both when the supporting internodes were free & when they were secured tied up; but was perhaps most conspicuous in the latter case or when the whole shoot was inclined. The tendril forms an acute angle, or is almost parallel, with the shoot, young shoot, small half-formed, from terminal internode; which rise alone its at the base of which & its straightening & stiffening; & the stiffening always occurred, as it approached & had to pass in it revolving revolving course & its own the young turned internode. Had it not thus Did not the tendril act acted behaved, it would have struck against the young intermediate been arrested by it. (a) As soon as the main & two lateral branches of the tendril begins, in this remarkable manner, to stiffen itself themselves, as if by a process of turgescence, & to rise from an inclined into a vertical position, the

[141v]

(a) Unlessthe tendril thus behaved acted, it would strike against the young terminal internode & be arrested by it. In thus moving rising vertically it cuts off a part of its proper elliptic or circular course.

[141v]

[Fragment, top and bottom of page excised & scored]

the whole revolution

revolved in a circle, it would strike against & be arrested by the young shoot above. I was always interested by watching how the curious manner which the tendril passed the it's the shoot; after travelling on, in one case observed at an angle of 37° with the horizon, & slight bowed downwards, as it neared the

(142

 

(Tendrils Cucurb:)

movement plainly becomes morerapid; & as soon as the tendril has succeeded in passing the passed its one young internode, its one movement revolving motion coinciding with the eff that from it's the effect of gravity often causes it to move unequally, whilst falling fall into its origin former previously inclined position, as the b so quickly that the end tip extreme end of the tendril could can be distinctly seen travelling like the minute hand of a gigantic clock.─

The tendrils are thin, from seven to nine inches in length, with a pair of short lateral branches rising not far from the base. The tip is slightly but permanently curved so as to act to a certain certain limited degree as a hook.

The concave side of the tip is highly sensitive to a touch, but not (as likewise observed by Mohl s. 65 in other species of the Family) so the convex side; I several times repeatedly proved this by lightly rubbing five four or five times the convex side of one tendril tendril & only once or twice or twice twice or thrice once or twice the convex side of another tendril, & the latter alone moved be curled inwards; in a few hours after [illeg] one the latter had recovered itself themselves, I reversed [illeg]the process of rubbing, & always saw with a similar result. After touching

(143

(Tendrils Cucurb:)

the concave side, the tip became sensibly curved on one or in two minutes; & subsequently, if the touch had been at all rough, it became coiled into a helix. But the helix would after a time uncoil itself & be ready to act again. A loop of very thin thread (not weighed) only 1/16th of a grain in weight caused the tendril curve a temporary flexure in a tendril. One of my plants had two se shoots near each other, & the tendrils were repeatedly drawn across each other, but it is a singular fact that they did not once catch each other. (a) The

I repeatedly rubbed rather roughly the basal lower parts of the middle tendrils, but never produce caused any curvature; yet if this part come are sensitive to prolonged pressure, for when they came into contact with a stick, they bent slowly bentround it.)

(The revolving movement is not stopped by the tip extremity curling free after bring slightly rubbed. When one of the

[142]

[The paragraph below scored]

(Tendrils Cucurb:)

quickly as to be plainly visible like the minute hand, of a gigantic clock. The tying of the internodes seemed to interfere greatly with the tendril passing to terminal shoot; & I presume believe that when the internodes are free they aid the passage by themselves curving down their own natural downward curvature at this point

[143v]

(a) One it would appear as if they had become habituated to contact of another other tendrils for the pressure thus caused, apparently will would be greater than that caused by a loop of soft thread weighing only the one-sixteenth of a grain

So it would appear that the tendrils are habituated to the drops of water or to rain; for artificial rain made by violently flirting a wet brush produced not the least effect on them.—

(144

(Tendrils Cucurb:)

lateral branches of a tendril had clasped clasps an object, the long middle stem continues revolving to revolve. (a) (a tendril does not long retain its revolving power; it then as soon as this ceases, it bends downwards & contracts spirally. After the But after the revolving movement has ceased, the tip still retains for a time its sensitiveness to contact, but this can be of little service to the plant.)

(Though the tendril is hi highly flexible & though the extremity travels under favourable circumstances at about the rate of an inch in two minutes and a quarter half a quarter, yet its sensitiveness to contact is so great that it hardly hardly ever failed fails to seize a thin stick placed in its course path. In observing this But. The following case case surprised me much: I placed a thin smooth cylindrical stick (& I repeated the experiment seven times) so far from a tendril, that its extremity could only curl half or three-quarters round the stick; but I always found

[144v]

(a) When a branch bearing on action tendril is bent & tied down down & secured so that the its tendril depends but is left free to move; its previous revolving movement is is nearly or quite at once at once arrested stopped, but it down begins to rise in a vertical plane, & as soon as it has become horizontal again attained rises above some a position inclined to way above the horizon, it recommences the revolving movements recommences. I tried this twice: in one case four times: generally the tendril became horizontal in one hour or in one and a half, but in one case, which the tendril was made to depended at an angle of 45° beneath the horizon; in the movement took two hours; it became horizontal & in another quarter of an half-hour had risen it rose to 23° above the horizon & then the revolving movement recommence began; ultimately it rose to 53° above the horizon. This upward vertical movement is independent of the action of light, for it took place once in the dark & on another time with the light lateral the light coming in on one side alone: it is the movement no doubt is guided by the opposition to the force of gravity, as in the case of the ascent of the plumules of the germinating seed.)

Their movement greater part of that this upwards vertical in the tendril took place in the dark; & as we shall hereafter see, a guiding stimulus is probably apparently in opposition to the attraction of gravity gravity.)

(145

(Tendrils Cucurb:)

in the course of a few hours that the tip had managed to curl twice or even once even thrice quite round the stick. I at first thought that this was due to rapid growth; but coloured measuring by coloured points & measurements I proved that there was no sensible increase of length of growth. When a fla square twig made square or a thin stick flat on one side, was similarly placed, the tip of the tendril could not curl itself curl beyond the flat surface, but instead coiled itself into a close flat helix, which turning to one side lay flat on the little flat surface of wood. In one instance a length portion of tendril, three-quarters of an inch in length was thus dragged on to the wood flat surface by the curing of the helix. But the tendril has thus acquires a very insecure hold & generally drops slips off: in one instance case alone, the helix subsequently uncoiled itself & the tip then forming passed round & clasped the stick. These cases of the formation of the helix on the flat surface show apparently shows

(146

(Tendrils Cucurb:)

as that the continued striving it is the tendency although of the tip to curl closely inwards gives the force which drags the tendril round a smooth cylindrical stick. In this latter case, whilst the tendrils were are slowly & quite insensibly crawling onwards, I several times observed through a lens that the whole surface was not in close contact with the stick; & I can only understand the onward curl closely inwards crawling movement, only by supposing that it is slightly versicular; vermicular;— or that the tip alternately straightened itself a little then curls inwards, & thus draging dragging itself inwards onwards but an insensibly slow alternate movement, (a)

However this may be, the fact is certain that one of these a tendril, which has caught a stick by its extreme point, can work itself onwards, until it has passed twice round & permanently secured grasped the stick.—

[146v]

(a) , which may be compared to that of a strong man holding on suspended by the end of his fingers to a horizontal pole, & working them on till who works his fingers onwards, until he can grasp the pole with his whole the palm of his hand.

[the paragraph below is scored]

(B); in this latter plant, Dutrochet (Tom Comptes Rend. Tom. 17 p. 1005) saw the movement of the tendrils reversed.

(146A

(Tendrils Cucurb:)

Hanburya Mexicana. — Both the young internodes & tendrils of this anomalous member of the family revolve in the same manner & at about the same rate as those of the Echinocystis. (a) The concave tip of the tendril is very sensitive; after coil rapidly coiling into a loop from a single touch it straightened itself in 50'. The tendril I mention this plant chiefly as illustrating one curious point in the description of the last species. The tendril when in full action, stands vertically up, with the young curled end of the shoot thrown a little on one side at of its the way; but the tendril it bears near the its base, on the inner side, a little short branch, which projects out at right angles, with its terminal part bowed a little downwards. Hence, as the main vertical branch revolves, the rectangular spur is part of the course is passed laterally against the curled end of the young shoot, & in another part of the course is carried a very little way from it; but from its

[146Av]

(a) It does not twine, but can ascend an upright stick by the aid of its tendrils.

(146B

(Tendrils Cucurb:)

rectangular position & from its being rigid, it cannot pass over the shoot end of the shoot, in the same curious curious manner as which the twine all thebranches of branches of the tendril of the Echinocystis did do by stiffening themselves at the proper point; so that the sweep of the lower part of the tendril of the Hanburya is but small much restricted. Hence a nice case of co-adaptation comes into play: in all the other tendrils seen by me all the branches become sensitive at the same period: had this been the case with the Hanburya the rectangular spur branch from being pressed against the ben curled bending curled end of the young shoot, would infallibly have seized it in a an useless or injurious manner. But as it is the main tendril after revolving for a time in a vertical position spontaneously bends down;— & in this of course raises the rectangular branch, which itself also curves upwards; so that by these combined

(146C

(Tendrils Cucurb:)

movements the branch rises above the end of the shoot & can now move freely without touching it; & then, & not until then, it f acquire first becomes sensitive.*

(Of other Cucurbitaceæ, I observed that the tendrils were sensitive & revolved, in Cucur Bryonia dioica, Cucurbita orifera, & Cucumis sativa; in this latter plant Dutrochet* (* Comptes Rendus Tom. 17. p. 1005) saw the movement of the tendrils reversed; but whether the internodes, as well as the tendrils revolved in these several plants,

(146D

[Archivist's note:] Follows * on p. 146C

(The extremity tips of the main & spire like both either both branches of the bas tendril, when, [illeg] it comes when with they come into contact with a stick, grasps it, like any ordinary tendril. But In a few days afterwards the inferior surface of the tendril over a space for a length of from half to one inch & three-quarter which is in contact with the wood, it for a length inferior surface swell & became which lies in contact touches the wood, over along a length developed itself into a cellular layer, which, closely adapt itself closely to the wood & firmly adheres to it. This layer is analogous to the adhesive discs formed by the tips of the tendril of in B. Cap. & littoralis; but here it in the Hanburya the layer is developed along half a length the terminal part of the tendril, from half to one 1 3/4 of an inch in length; somewhere for a length of one inch & three quarter but not at the extreme tip which in cold also h & l [illeg]This layer is white, whilst the tendril is green, & near the tip it can could sometimes have seen to be sometimes thicker than the tendril itself; it is als generally broader than spreads beyond the sides of the tendril, & its edge, is fringed with free elongated cells, which have enlarged globular or retort-shaped extremities heads.

This cellular layer appearing adhere by an secreted some resin cement; for it adhesion to towards was not lessened by immersion in alcohol for during 24°, but in was quite so loosened by immersion during the same this time by the action of ether & [illeg] for during the same period.

[[146E]

When the tendril has [illeg] firmly coiled by either branches round a stick it is not easy difficult to imagine of what are the adhesive cellular layer can be. owing to the spiral contraction a whole [illeg] after its tendril [illeg] into action with [illeg] the tendril of by [illeg] was unable to remain in contact with a thick perch on nearly flat surface; if they in this are is it [illeg] the [illeg] & in such cases friction of the an adhere layer would might here be of [illeg] service to the plant.)

if they had so remained & the adhering layer had been formed; if they could could have had been so [illeg] & had become attached to such objects by the they are adhere cellular layers its friction could have been of service to the plant.)

[note added in another hand:] continued on p. 146C, after asterix

[146Ev]

vertical

(147

(Cucurb Tendrils:)

likewise revolved. I did not observe. but in

In The Anguria Warscewiczii, however, the internodes, though thick & stiff, did revolve. In Zanonia Indica, which belongs to a different tribe of the Family, the forked tendril & the internodes revolve, in periods between 2° 8' and 3° 35', & moved against the sun.─)

Vitaceæ — In this family & in the two following, namely, the Sapindaceæ & Passifloraceæ, the tendrils are modified flower-peduncles; so that they are axial in their nature.

In this respect they are more nearly allied related to those of Corydalis some of in the Fumariaceæ (& which family according to Lindley the Vitaceæ are allied) & according to several another related to those ofthe Cucurbitaceæ, according to the authors who consider the tendrils in this latter family as modified branches. But the homological nature of a tendril seems to make no difference in its action.)

(148

(Tendrils vitaceæ)

Vitis vinifera.─ The tendrils are thick & of great size; & one from a vine not growing well out of doors & not vigorously, measured 14 1/2 sixteen inches in length. It is necessary, as we shall see, to describe them. The tendril each consists of a foot-stalk, bearing two branches, which diverge equally from it the foot-stalk.

One of these branches branches has a scale at its base; and & hence, I presume, may be considered as a branch from the other; yet this one and is is always, as far as I have seen, longer than the other, & and very often bifurcates. The branches when rubbed become curved to that side, & subsequently straighten themselves. When they have naturally permanently clasped any object they contract spirally; but this does not occur (Palm s. 56) when no object is has been seized. so it is with the two other following genera in this family. The tendrils move spontaneously from side to side; & on a very hot day one made two elliptical revolutions, each in at an average rate of 2° 15'. During these movements if a a coloured line be painted on the convex

(149

(Tendrils vitaceæ)

along the convex surface of the a tendril, became first lateral & then concave. The separate branches of the tendril have independent movements. After the a tendril has spontaneously moved for revolved for a time, it turns itself bends from the light towards the dark: I do not give this latter fact on my own authority, but there is abundance but on that of Mohl & Dutrochet. Mohl (s. 77) says that in a vineyard the tendrils generally point to the north vine planted against a wall the tendrils point towards it, & in a vineyard generally more or less to the north.

(The young internodes exhibit some little spontaneously revolve; revolving movement; but in no other case have I seen so feeble a mover slight a the movement. I do

A shoot faced a window, & I traced on the glass during two perfectly calm & hot days the movement its course; of the shoot, which may be during ten hours on one day, it described as an elliptical a spire, representing two and a half ellipses. & which we performed I likewise place a

(150

(Tendrils vine)

bell-glass over a young muscat grape in the hot-house, & it made three or four extremely oval revolutions each day: the during each of two days; the plant had not been moved & long stationary & during one whole day, was the sky was uniformly overcast or that the movement could hardly be The shoot moved not more than so much as half-an inch from side to side; & had it not made clos at least three revolutions during the day, I should have attributed the movement motion to the varying action of the light. The extremity of the shoot is always bowed downwards; & more or less curved; bent downwards; but this part does not never reverses its curvature, as so commonly happen occurs with twining plants.

(Various authors (Palm s. 55, Mohl s. 45. Lindley Lindley &c) have spoken of the believe that the common or true tendrils of the vine are modified flower-peduncles. & certainly the evidence is striking. I here give a drawing of the ordinary state of one a flower-peduncle (Diagram 9. 7) a branch of flower buds tress of flowers in bud, consisting of the "common peduncle"─ foot-stalk, A; corresponding to that of the tendril. of the "flower-tendril", B, which has been naturally is represented as having caught a twig twig; & of the true flower stalk in "sub-peduncle"

"sub-peduncle", C, with bearing the flower-buds.

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(Tendrils vine)

, C, ─ as it the second part here may be called. (a) The flower-tendril, B, is always longer than the true flower-stalk sub-peduncle, & has a scale at its base: it sometimes bifurcates, & therefore correspond in every respect with the longer, scale-bearing branch of the [illeg] true tendril. excepting that it does not diverge equally in from bends backwards bends It, however, at right angles or backwards from the other branch branch or true flower-stalk & so far differs; which it this seems to be an adaptation for the flower-tendril to. It bends, however, either backwards or at right angles or backwards angle from the true flower stalk sub-peduncle, C, & is thus adapted to aid seize any one obj or support in [illeg] a position, as to aid in carrying the future bunch of grapes.

The flower-tendril when rubbed, curves & subsequently straightens itself; & it can, as shown in the drawing, securely clasp a support a supporting object.─I have seen even so an object as soft an object as contact with one of its own leaves as as a young vine-leaf caught.) by one.) cause it to curl.─

(The lower & naked part of the true flower-stalk sub-peduncle (C)

[151v]

(a) The whole flower-peduncle peduncle moves spontaneously, especially when it the sub-peduncle does not bear many flower-buds, like a true tendril, but in a lesser degree,. The common foot-stalk peduncle, A, manifestly corresponding to that of the true tendril, in neither case flower nor tendril has not the power of clasping a support, nor has the corresponding part in the true tendril.─

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(Tendrils vine)

is likewise slightly sensitive to a rub & I have seen it distinctly bent half-round a stick & even partly round a leaf with which it had come into contact.

That the true flower stalk sub-peduncle has the same nature as the corresponding branch of an ordinary tendril, is beautifully well shown, when it bears only a few flowers; for in this case it becomes less branched, increases in length, became gains both in sensitiveness & in the power of spontaneous movements movement. I have seen two true but considerably elongated sub-peduncles flower-stalks (as if drawing) which bore, bearing only from 30 to 40 flower-buds, which were elongated than which had become considerably elongated & had completely wound round it by their middles round sticks exactly like true tendrils. To show the gain gain of sensitiveness I took a The whole length of another sub-peduncle true flower-stalk, bear bearing only eleven flower-buds, & I found that every part of the it soon became curved when slightly rubbed; often rubbing; but it was striking to observe that the curvature was less ensued more slowly

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but even this scanty number of flowers rendered the stalk less sensitive than the other branch or flower-tendril; or a dry other branch or flower tendril; for it required a the for the latter required often a sl lighter rub & then rather harder rub & this bec bent became became curved in a lesser a greater higher degree & less more quickly, than I have also seen the sub-peduncle with its few flowers. in a densely covered a flower-stalk partly a sub-petiole thickly covered with flower-buds, one of the higher but with a single one of the higher lateral branches which bore bearing from some cause only two buds & this one little branch had become much elongated & into a tendril & had naturally caught hold of an adjoining twig and in fact formed a little tendril. The increase of length (a)

(With respect to the common foot-stalk (A) I am assured by a person whom I can trust, that it will occasionally clasp wind round a support; & the but I have never seen with the footstalk of a common tendril. The whole flower-stalk spontaneously moves, like a common tendril, but I believe in a less degree. From the facts now already given

[153v]

(a) of the flower-stalks sub-peduncle with the decreasing number of flower-buds is a good case of instance of the law of compensation"

[text pasted over] true tendril bearing

It was with Hence it is, that the whole ordinary tendril is longer than the whole flower-peduncle; for instance in one old vine, the same plant, the longest flower-peduncle (measured from the base of the common peduncle to the tip of the flower-tendril) was 8 1/ eight & a half inches in length, whilst the longest tendril was nearly double this length namely sixteen inches.) in length.)

[4 lines scored]

longest [text pasted over]

of the common to the tip of the flower-tendril) in the same plant was only 8 1/2 inches in length.)

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(Tendrils vine)

(The gradation of from the ordinary state of a flower-peduncle, as represented in the drawing, to that of a true tendril is perfect. We have seen that the "true flower stalk" sub-peduncle (C), whilst still bearing from 30 to 40 flower-buds, becoming becomes somewhat elongated & partially assumes all the characters of acting like a tendril floret the corresponding branch of a common the true tendril. From this stage state we can trace every step stage till we find come to a le may full-sized perfect tendril, bearing on the branch which corresponds with the sub-peduncle & flower bud! Hence there can be no doubt that the tendril is a modified flower-peduncle.)

[154A]

peduncle.

(Another kind of gradation in an opposite direction well deserves notice. The flower-tendril (B. of the drawing) sometimes produce a few flower-buds: I found 13 and 22 on two flower-tendrils on a vine growing against my house; But in

[text pasted over] flower-buds thus

in the state they retained their characteristic qualities of sensitiveness & spontaneous movement but in a somewhat lessened degree. On vines in hot-houses, so many flowers are occasionally produced by the flower-tendrils,

(155

(Tendrils vine)

that a double branch of grapes is produced, the result which is technically called by gardeners a "cluster". In this state the whole flower-stalk peduncle presents scarcely any resemblance with to a tendril; & judging from the facts already given it would probably possess little or no sensitiveness or power of clasping a support (or of spontaneous movement.

In this state the whole flower-stalk would per exactly Such flower-peduncles closely resemble in structure those that borne by the next genus of the vitaceæ, namely Cissus. This genus, as we shall immediately see, produces well-developed tendrils & of course ordinary bunches of flowers; but there is no gradation between them. If the genus Vitis were unknown had become extinct, the boldest believer in the modification of species would never, I suppose, have continued to surmised surmised that our pl the same individual plant, at the same period of the same of growth, would have yielded every possible the almost every possible finest gradation between tendril, used for climbing, & flower-stalks

(156

(Tendril Cissus)

common stalks ordinary flower-stalks for the support of the flowers & fruit fruit, & tendrils seed used exclusively used for climbing. But the uses Vine shows us clearly gives us this clearly case; & it makes the use of the best & most curious cases of gradation is seems to me as striking & curious an instance of a case of gradation or transition as can well be conceived.)

Cissusdiscolor.— The young shoots which are bent downwards do not spontaneously revolve, or show no more movements that can be accounted for by the changes in the varying the action of the varying light, & by growth.— The branches of flowers do not revolve, but the daily variations in the action of the light. The tendrils, however, revolve, following the sun, revolve with much regularity & in the cases the case observed by me, swept a circle circles of about five inches in diameter.

Five circles were completed in the following times 4° 45', 4° 50', 4° 45', 4° 30' and 5° 0'.— The tendril are about from 3 1/2 to 5 inches in length; they stand vertically

(157

(Tendril Cissus)

The same continues revolving during three or four days. The tendrils are from 3 1/2 to 5 inches in length: they are formed of a long footstalk, bearing two short branches, which in old plants again bifurcate. The two branches are not of quite equal lengths; & as in with the vine, the longer one has a scale at its base. The tendrils stands vertically upwards; & the extremities of the young shoot are bent abruptly downwards, & this position is probably of service in keeping them out of the way of the revolving tendril.

[157a]

the revolving tendril. [text excised]

one tendril continues revolving during three or four days.— The tendril It consists of a long footstalk, divided at the end into two branches, which in old plants again to bifurcate: (a) (The two branches, whilst young are highly sensitive; for I found a touch with a pencil so gentle as only just to move the whole tendril which was borne at the end of a long flexible shoot f stem stem, sufficed to cause it to become perceptibly curved in four four or five minutes: the branch became straight again in rather above one hour. A loop of soft thread weighing 1/7th of a grain, thrice stands caused the one the tendrils was thrice tried & caused the tendrils to b become curved in 30' or 40': half this weight produced no effect.— The long footstalk is much less sensitive; for slight rubbing produced

[157av]

[page scored]

(a) The two branches are not of quite equal length, & as in the vine the longer one has a scale at its base.) The

(158

(Tendril Cissus)

no effect; but prolonged contact with a stick caused it to bend round. The two terminal branches are sensitive on all sides; & if the two of one tendril were just touched on their inner side a number of tendrils can be just touched at the same time in on different various sides; the two branches of one on their inner sides; two others on their their outer sides, or both branches on one either one side, in about quarter of an hour, they presented present a curiously different appearance. but each one is symmetrically curved.

If a branch is be at the same time with equal force on opposite sides, both sides are equally stimulated & no there is no movement; previously to examining this plant, at the beginning of my work, I had observed only three tendrils alone which are sensitive on one side alone, & these when lightly pressed between the finger & thumb become curved well; but on thus pinching th many times the tendrils of this Cissus no curvature ensued, & I was at first led falsely to infer that they were not at all sensitive sensitive to a touch.—.

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(Tendril Cissus)

Cissus antarcticus. — The tendrils on my young plants were thick & straight, & undivided but with the tips a little curved; when their concave surface were rubbed with some force, they very slowly became curved & subsequently became straight again very slowly straightened themselves. Hence they are much less sensitive than those of the tendrils of the last species; but they revolved made two revolutions, following the sun, rather more rapidly, viz in 3° 30' & 4°.—

The internodes do not revolve.—

Ampelopsis hederacea (or Virginian Creeper). — In In this allied plant, likewise the Virginian creeper, the which is allied closely to the last genus, The internodes do not move more than apparently can be apparently accounted for by variations in the the varying action of the light. The tendrils are from 4 to 5 inches in length, the main stem sends off several lateral branches, (a) They exhibit no true spontaneous revolving movement; but turn, as was long ago observed by

[159v]

(a) , which have their tips curved, as may be seen in Fig 8. 10 A.

(160

Andrew Knight* from the light to the dark: I have seen several tendrils move through an angle of 180° to the dark side of a case in less than 24 hours a day 24 hours; but the movement is sometimes very much slower. The several lateral branches often move independently of each other & sometimes irregularly without any apparent cause. cause.

It is a remarkable & these tendrils, are the only ones seen observed by me, which are not sensitive & do not curve often being lightly rubbed; yet they must in some slight degree be sensitive to prolonged contact, for to be many tendrils of from a plant, which grew over a tall box-tree, clasped the branches, but this would act when nake thin sticks were placed in contact with. The tendrils of a plant in a pot, after touching when placed in contact with thin sticks, withdrew themselves; & in in one instance above showed a feeble tendency to curl round one a stick.— When the tendrils move came into contact with a flat surface of wood or wall, & this is evidently what they

[160v]

* Transact. Phil Soc. 1812. p. 314

[160A]

These tendrils are less sensitive to contact a touch than any others observed by me: by slight gentle but repeated rubbings with a twig, the lateral branches, but not the main stem, became in the course of three or four hours slightly curved; but they seemed to have but slight hardly any power of straightening themselves. A plant

The tendrils of a plant which had crawled over a large tall large Box-tree clasped some several some of the branches. But I have several times repeatedly seen the tendrils come into contact with sticks, & then withdraw from them. When they come into meet with a flat surface of wood or a wall, & this evidently which they

(161

(Tendrils Ampelopsis)

are adapted for, they turn all their branches towards it, & spreading them widely apart, bring their hooked tips laterally into contact with it. In effecting this, the several branches after touching the surface, often rise up, place themselves in a new position & again come down into contact with it.)

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are adapted for, they spread out all their branches & turn their curved tips laterally & bend their tips down to it C (B. Fig 8); to the surface of wood or wall, so that the assume they assume the position of a hand, with the fingers div widely stretched apart, but all resting on their tips: in effecting this, the several branches after touching the surface, often often arise fr & arranging place arrange themselves in a new position & again come again into contact with it. But they place almost always their tips of the branches which are a little curved or hooked, laterally on the surface.)

(A In the course of about two days, after a tendril has arranged its curved tips laterally in contact with a hard all its branches so as to press on the any & flat surface, the curved tips swell, became bright red & form on the under sides the well-known little discs or cushions, by which adhere firmly to the surface. In one case the tips of the became slightly swollen in 38° after coming into contact with a brick; in another cases they were considerably swollen in 48° & in an additional 24° they discs were firmly attached to a smooth board; & lastly the tips of a younger tendril not only swelled but became attached to a stuccoed wall in 42°.— These adhesive discs resemble, except in

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(Tendrils Ampelopsis)

colour & in being larger those of Bignonia capreolata. (a) They are never produced developed, as far as I have seen, without the stimulus of at least temporary contact with some body. object. They are generally first-formed developed on one side of the curved tip; the whole of which often became so changed, that only a line of green unaltered tissue can be traced only along the concave side surface. When, however, a the end of tendril clasps a cylindric cylindrical stick the red cellular are a long irregular rim line or disc or outgrowth is formed some little distance along the inner surface in contact of with the stem or the branches of the tendril of the tendril at some little distance from the curved tip: this was also observed (s. 71.) by Mohl. The discs consist of enlarged cells, with smooth projecting hemispherical surface, coloured red, & at first grasped with fluid (see section, give by Mohl s. 70), but ultimately they ultimately soon afterwards & soon became woody.) (As the discs can almost immediately can immediately adhere directly after their first formation can so quickly adhere firmly to such smooth surfaces, as planed & planed & painted, wood, & or the polished leaf of the Ivy, this alone

[162v]

(a) As with this plant, When they discs were developed in contact with a ball of tow, the fibres were separately enveloped, but not to so large a extent as with B. capreolata. Discs are

(163

(Tendrils Ampelopsis)

would render it probable that some cement is secreted, as as it appears (Mohl s. 71) has been asserted to be the case stated to occur (quoted by Mohl s. 71) by Malphighi. I removed a number of discs formed during the previous year from a stuccoed wall, & placed them in warm water, diluted acetic acid & alcohol during many hours; but the attached grains of sand silex were not loosed loosened: immersion in sulphuric ether for 24° loosened them: but warmed essential oils (I tried oil of Thyme & Peppermint) in the course of a few hours completely completely loosened released every atom of stone. This I think prove seems to prove that some resinous cement is secreted. (a) But It must not be supposed that the attachment is by any means exclusively effected by the cement; by any cement of this nature; for the cellular outgrowth completely all envelopes every minute & irregular projection, & inserts insinuates itself into every crevice.)

A tendril which has not become attached to any body, does not contract spirally; & in course of a week or two, it shrinks into the

[163v]

(a) The quantity secreted, however, must be small, for when a plant ascended a thinly white-washed wall, the discs adhered firmly to the white-wash; but never as the cement never penetrated the thin layer, so that scales they discs were easily withdrawn dragging together with these little scales of the white-wash.

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(Tendrils Ampelopsis)

finest thread, withers & drops off. An attached tendril, on the other hand, contracts spirally & is & thus becomes highly elastic; so that when the main main contact stem footstalk is pulled to strain strain is equally distributed to all the attached discs.

For a few days after the first attachment of the discs, the tendrils remain very weak & little, but in a few more days the they increase much in thickness & (a) are spirally contracted branch stalks main stem & bundle great branches have acquired more strength; that & it is a good proof how completely that this change is the natures of the tissues, as well as, & the act of of the tendril & its spiral contraction depends is consequent on the formation of the disc, that is well shown by any lateral branches which have not become attached; for they wither & drop off in a week or two, withering & dropping off, thus like as does in the same manner as does a whole tendril, when unattached. the whole unattached tendril, when no discs have been formed. The change The gain in strength & durability & even in of the attached tendrils is really after the attachment of their discs is something quite wonderful. There are tendrils now adhering to my house, which are still strong strong & have been exposed to the weather for 14 or 15 years. One single lateral branchlet of a tendril, which almost estimated to be at least

[164v]

(a) acquire great strength. In the accompanying diagram (Diagram 10 8.) we can compare the differences of a tendril (B.) some weeks after attachment to a wall, with one (A.) from the same plant, fully grown but unattached. That this change in the nature of the tissues of the tendril, as well as the act of spiral contraction, is consequent on the formation of

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(Tendrils Ampelopsis)

have been must be have been ten years old, was still high elastic & supported exactly a weight of two pounds. weight. This tendril had five such disc-bearing branches bearing with disc of equal thickness & apparently of equal strength; so that this one this one tendril would have safe, though having been, after, although it had having been exposed during ten years to the weather, would have supported resisteda strain of ten pounds!)

Sapindaceæ — Cardiospermum halicacabum. In this Family, as in the last, the tendrils are modified flower-peduncles. In the present plant, there are no organs exclusively used for climbing, like the true common ordinary tendrils; of the but two of the of the branches of the flower-stalk in same peduncle stalk peduncle which bears the flowers & first & are thus used & are have been converted into a pair of tendrils, corresponding with the single "flower-tendril" of the common vine. The flower peduncle is thin, & stiff, and from 3 to 4 1/2 inches in length. Near the summit, above two little bracts, it divides into three

(165A

(Tendrils, Cardiospermum)

branches. The middle one divides & re-divides again, & carries bears the flowers; ultimately it grows half again as long as the two other branches.

These latter are the tendrils; they are at first thicker & longer than the middle one branch, but never become more than an inch in length. They taper to a point & are flattened, with the lower clasping surface destitute of hairs. At first they project straight up; but soon diverging, they spontaneously curl downwards so as to become symmetrically & elegantly hooked, as represented in the diagram. (Diagram 9. 11.) [Climbing plants, fig. 12, p. 150] They are now, whilst the flower-buds are still small, ready for action.)

(The two or three upper young internodes steadily revolve: & make those on one plant made two circles, against the course of the sun, in 3° 12'; in a second plant the same course was followed, & the two were completed in 3° 41'; in a third plant, the internodes followed the sun sun & made it two circles in 3° 47'. The average rate of these six revolutions was is

(165B

(Tendrils, Cardiospermum)

1° 46'. The stem shows no tendency to twine spirally round a support; but the allied tendril-bearing genus Paullinia which bears tendrils is said (Mohl s. 4) to be a twiner.—

By the above revolving movement the flower-peduncles are carried round & round; but when the internodes we were securely tied the long & thin peduncles, itself is themselves were seen to be in continued & sometimes rapid movement from side to side. It They swept a wide space, but only occasionally made moved moved in at all a moderately regular elliptical course.

By these combined movements either one, & sometimes both of the short, hooked, tendrils, which project above the tip of the shoot are at catches hold of some surrounding object, twig or branch which they & then it curls round & securely grasps it. These tendrils, are, however, but slightly sensitive: by rubbing their under surfaces only a slight movement is slowly produced. I hooked a tendril on to a twig; & I found that in 1° 45' it had curved considerably inwards; in 2° 30' it formed a ring; & between in from 5° to 6°, from being first hooked, it closely grasped the

(165C

(Tendrils, Cardiospermum)

stick: a second tendril bet acted at nearly the same rate; but I have observed one that took 24° before it had pressed curled twice round a thin twig. If Tendrils which have caught nothing, ultimately after the interval of several days, spontaneously curl closely up into a helix. Those which have curled round some object soon became rigi a little thicker & tougher. The long & thin main peduncle, though spontaneously moving, is not sensitive & never curls round any a support. It does not never contract spirally & this is an unusual circumstance. Such contraction would apparently have been of considerable service to the plant in climbing; nevertheless it climbs pretty well without this aid. The seed-capsules though light, are of enormous size (whence hence its English name of Balloon-vine), & as several two or three are carried carried on the same peduncle, the flower-

(165D

(Tendrils, Cardiospermum)

tendrils being arising close to them, may possibly be of additional service in preventing preventing these balloons from being dashed to pieces by the wind.

In the hot-house they served simply for climbing.)

The position of the tendrils alone suffices to show their homological nature: but in two instances one of two tendrils produced at its tip a flower; but this did not prevent the tendrils acting properly & curling round a twig. In a third case, all these branches both which ought to have been changed into tendrils produced several flowers, & the two lateral branches which ought to have existed as tendrils, both produced flowers like the central branch, & had quite lost their tendril-structure.)

(I have seen, but was not enabled carefully to observe, only one other climbing Sapindaceous plant, namely Paullinia. It was not in flower, yet very differently from Cardiospermum bore fine long

[165D]

Cardiospermum bore fine long forked tendrils. So that in its tendrils, Paullinia apparently bears the same relation to Cardiospermum, that Cissus does to Vitis.)

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(Tendrils Passiflora)

Passifloraceæ — It is scarcely possi After reading the discussion & facts given by Mohl (s. 47) on the nature of the tendrils in this Family, one cannot doubt that they are modified flower-peduncles. My son Mr W. E. Darwin, made sketches The tendrils & true flower-peduncles rise close side by side, & my son, Mr W. E. Darwin made sketches for me of their earliest states of development in the hybrid P. floribunda. The two papillæ organs at first as cohere & appear as a single papilla, which gradually divides; whether this indicated that the so that I presume the tendril is an aborted branch of the the flower-peduncle. as in the cases of the vine. My son found one case in which the very young tendril was surmounted by traces of floral organs exactly like those on the summit of the true flower-peduncle at the same early age.)

(166A

(Tendrils Passiflora)

Passiflora gracilis. — This well-named, elegant, annual species differs from all the other members of the group observed by me, in in the young internodes having the power of revolving.

It exceeds all the other climbing plants observed by me, in the rate of rapidity of its movements revolutions, & all tendril-bearers in the sensitiveness of its tendrils. The internode which carries the upper active tendril which at the time is f in mature,& which likewise carries one or two younger immature internodes, made three revolutions, following the sun, at an average rate of 1° 4': it then made, the day becoming very hot, three other revolutions at an average rate of between 57' & 58'; so that the average rate of all six revolutions was 1° 1'. The apex of the tendril described sometimes narrow & long & sometimes broad & longer long ellipses, with their longer axes inclined in rather slightly different directions. The plant can ascends a thin upright stick, by the aid of its tendrils; but

(166B

(Tendrils Passiflora)

the stem is too stiff for it to twine spirally round it, even when not interfered with by the tendrils, which were successively pinched off as each are formed.) at an early age.)

When the internodes were secured stem was tied to a stick, the tendrils were seen to revolve in nearly the same manner & at the same rate as the internodes. The single tendrils are very very thin & delicate, delicate & straight, excepting the tips which are a little curved; they are from seven to nine inches in length. A half-grown tendril was not sensitive; but when nearly full-grown, they are extremely sensitive. A single delicate touch on the concave surface of the tip soon caused it to curve, & in two minutes it formed an open helix. A loop of soft thread weighing 1/32th of a grain equal to only two millimetre & placed most gently on the tip, thrice plainly caused the tip it to become curved curve; as did twice a a bent bent bit od thin platina wire,

(166C

(Tendrils Passiflora)

weighing the 1/50th of a grain (    milligrammes); but this weight, when left suspended, did not suffice to cause permanent curvature. These trials were made under a bell-glass, so that the loops of thread & wire might were not be agitated by the wind.

The movement after a touch is very rapid: I took hold of the lower part of the several tendrils & then touched them with a thin twig their concave tips, & watched it them carefully through a lens; the tips plainly began to bend in the following times, 31", 25", 32", 31", 28", 39", 31", 30": so that the movement was generally perceptible in half a minute after a touch; but on once certainly & plainly in 25 seconds after a touch. One of the tendrils which thus became bent in 31", had been touched two hours previously

(166D

(Tendrils Passiflora)

& had coiled into a helix: so that in this interval of two hours it had straightened itself & had perfectly recovered its sensibility.)

(I repeated the experiment made on the Echinocystis & placed several plants of this Passiflora, so close together that the tendrils were repeatedly dragged over each other; but no curvature was caused ensued. I als likewise repeatedly & violently flirted small drops of water from a brush with long bristles on many tendrils & syringed others so violently that the whole tendril was dashed about but they never become curved. The impact from of the drops of water on my hand, was far plainer than that from the 1/30th the loops of thread (weighing 1/32th of a grain) when allowed to fall on it; & these loops which caused curvature were had been placed most gently on the tendrils. Hence it is clear either that the the tendrils are habituated to the touch of other tendrils & to that of drops of rain; or that they are sensitive only to prolonged, though excessively slight, pressure (a))

Passiflora punctata. The internodes do not move; but the tendrils regularly revolve. One that was about half-grown & very sensitive

[166D]

[addendum]

rain; or that they are sensitive only to prolonged, though excessively slight, pressure (a))

Passiflora punctata. The internodes do not move; but the tendrils regularly revolve. One that was about half-grown & very sensitive tendril made three revolutions, opposed to the course of the sun, in 3° 5, 2° 40' and 2° 50'; (B) The plant was placed in from of a window

[166D]

(a) (B): perhaps when grown to nearly its full length, it would have move travelled more quickly.

[166Dv]

(a) To show the difference in the kind of sensitiveness in different plants & likewise to show the force of the syringe used, I may add that the lightest jet from it instantly caused the leaves of a Mimosa to close close; whereas the loop of thread weighing 1/32 of a grain, when rolled into a ball & gently placed on the glands at the bases of the leaflets of the Mimosa, caused no action. Had I space, I could advance much more striking cases in allied plants, of one being excessively sensitive to the lightest pressure if prolonged but not to a brief impact, & another plant equally sensitive to impact, but not to slight & prolonged pressure.—)

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& I ascertained that, as with twining stems, so with these tendrils, the light accelerated the movement in one direction & retarded it in the another other; for the semicircle whilst travelling towards the light the semicircle was performed in one case in 15' in a second case in 20' quicker less than the other semicircle time required consumed

other; the semicircle towards the light being performed in one instance in 15' and in a second instance in 20' less time than that required by the semicircle towards the dark end of the room. Considering the extreme act tenuity of these tendrils, the well-marked strongly action of the light on them revolving movement is remarkable. The tendrils are long, & as just stated very thin, with the tip slightly curved or hooked. The concave side is extremely sensitive to a touch; as even a single touch causing it to curl bend curl inwards; (a) A loop of soft thread weighing 1/14th of a grain caused the extreme tip to bend; at another time I tried to hang the same little loop on an of t

[167v]

(a) it subsequently straighten itself, & is again ready to act.

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inclined drooping tendril, but three times it slided off; yet this extraordinarily slight degree of friction sufficed to make the tip to curl. in Though so sensitive the movement was not very rapid The tendril, though so sensitive, does not move very quickly after a touch, th no conspicuous change being observable until 5' or 10' have had elapsed.

The convex side of the tip is not sensitive to a touch or to a suspended loop of thread. In one instance I observed a tendril revolving with the convex side of the tip forwards, & in placing coming into contact with a stick placed in its way, in fact, it merely scraped up & past it, without any power of of clasping; the obstacle & was not able to clasp it; whereas when a stick tendrils revolved with the concave side of twig tips is forward, it promptly seized promptly promptly seized any object in their path.)

Passiflora quadrangularis. — This is a very distinct species. The tendrils are thick, long, & stiff: they are sensitive to a touch only towards the extremity & on the concave surface. [illeg] (in rate & direction; When a stick was placed so that the middle of the tendril came into contact with it, no curvature was caused. In the hothouse a tendril made two revolutions, each in 2° 22'; in my cool study one was completed in 3° & a second in 4°. The

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(Tendrils Passiflora)

one circle was completed in 3° and a second in 4°. The internodes do not revolve; nor do those of the hybrid P. floribunda.

Tacsonia mannicata. — Here again the internodes do not revolve. The tendrils are moderately thin & long; one made a narrow ellipse in 5° 20', & the next day a broad ellipse in 5° 7'. Being not The extremity being lightly rubbed on the concave surface, became just perceptibly curved in 7', clearly curved in 10' & hooked in 20'.) Having marked a tendril with a [text pasted over] colour, no effect was

(We have seen that the tendrils in the last three Families, namely, Vitaceæ, Sapindaceæ & Passifloraceæ are modified flower-peduncles.

This is likewise the case, according to Decandolle (as quoted by Mohl) s.  ), with the tendrils of Brunnichia, one of the Polygonaceæ. In two or three species of Modecca, one of the Papayaceæ, the tendrils, as I hear from Prof. Oliver bear flowers & fruit; so that at least they are axial in their nature.)

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(Spiral Contraction)

Spiral Contraction.— This movement which shortens the tendrils & renders them elastic, commences in from half a day or in a day or two after their extremities have clearly wound round any caught any some object. (a) It

There is no such movement in any leaf-climber, with the exception of an occasional trace of it in the petioles of Tropæolum tricolorum. On the other hand, it occurs with all tendril, after they — I refer here only to those that have seized some object, — with the few following exceptions, namely Corydalis claviculata, but then its tendrils still deserve to be this plant might be called a leaf-climber; Bignonia unguis & its close allies, and the Cardiospermum; but their their tendrils are so short that the movement contraction could hardly take place & would be quite superfluous. The tendrils of Smilax aspera though rather short, offers a more marked exception. In the tendrils of Dicentra, whilst young, the tendrils are short & do not contract spirally, but only became slightly flexuous; the longer tendrils, however, of the older plants contract spirally. I have seen

to the rule that all

[170]

[addendum]

whilst young, the tendrils are short & do not contract spirally, but only became slightly flexuous; the longer tendrils, however, of the older plants contract spirally. I have seen no other exceptions to the rule that all tendrils, after clasping by their extremities some object a support contract spirally

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[slip of paper pasted over]

(Spiral Contraction)

[illeg]

spirally. When, however, the tendril of any plant of which the stem happens to be immovably fixed, happ catches by its extremity some fixed object, it does not contract spirally, simply because it cannot; but this, however, rarely occurs. With the Cardiospermum & Mutisia the tendrils do not contract into a helix flattened spire or helix.

In the common Pea only the lateral branches & not the stem of the tendril does not contract; & is with most plants, such as the Vine, Passiflora, Cardiospermum, Bryony, the basal part of the common basal part portion of the tendril never contracts into a spire.)

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(Many The tendrils of many kinds of plants if they catch nothing, ultimately likewise contract after an interval of several days or weeks into a close spire; but the spontaneous in the cases the movement in this case takes place only when the after the tendril has lost its revolving movement power & has partly has ceased, & when the tendril has quit or wholly lost its sensibility, & hangs downwards: it is, as we shall presently see, a [text pasted over] movement, I did not make many

quite useless movement. The spiral contractions of unattached tendrils is a much slower process than that of attached tendrils: young tendrils which have caught a support & are spirally contracted mayconstantly seen on the same stem with much older & tendrils, unattached & uncontracted.

In the Echinocystis I have observed seen a tendril with the two lateral branches of the a tendril clasped the twigs & be forming contracted into beautiful spires, whilst the longer middle main branch ran which had caught nothing remained for many days uncontracted. In this plant I once observed that that this a main branch after catching a stick after it had caught a stick become spirally flexuous in 7° & spirally contracted in 18°. after its tip had caught a stick. Generally

begin to contract

[171]

[addendum]

plant I once observed that that this a main branch after catching a stick after it had caught a stick become spirally flexuous in 7° & spirally contracted in 18°. after its tip had caught a stick. Generally the tendrils of the Echinocystis begin to contract in from 12° to 24° after catching some object; whereas unattached tendrils do not generally begin to contract until two or three or even more days have elapsed after the revolving movement has

(a) , or, in the case of the Cardiospermum, into a helix.—

[171v]

(a) , or, in the case of the Cardiospermum, into a helix.—

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ceased. I will give one other case: a full-grown tendril of)

catching any object: it was apparently full acquired its full length in four days; in six additional days it first became flexuous, & in two more days formed one complete spire. This spire contraction commenced at first spire was formed towards the basal end of the tendril, & the contraction steadily, but slowly progressed towards the apex; but the whole was not closely wound up until 21 days had elapsed after from the first observation, that is until 17 days after the tendril was full grown.—

[172A]

Passiflora quadrangularis. — which had caught by its tip a stick began in 8° it began to contract & in 24° several spires were were formed: a younger tendril only two-thirds grown, showed the first trace of contraction in two days after clasping a stick, after catching by its tip a stick; & in two additional days had formed several spires: hence, apparently the contraction in a caught tendril does not begin in a tendril until at at full growth has been acquired. The tendril has it is grown to nearly its full length. Another young tendril of about the same age & length as the last, was prevented from

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(Spiral Contraction)

(The best proof of the intimate connection between this subsequent of the spiral contraction of a tendril & the previous act of seizing clasping a support is afforded by those tendrils which, in the latter case [illeg] from when caught invariably contract into a spire, whilst as any as they they remain are remain unattached, they continue straight, though dependent, & in this state though thus wither & drop off. The tendrils of some of all the species of Bignonia, which are modified leaves thus behave, as do those the tendrilswhich are modified flower-peduncles of the three genera of Vitaceæ,

(a) In Ampelopsis hederacea & in Bignonia capreolata, the it the formation of the adherent adhesion of the discs, & not the without any curling round a stick support, which determines the subsequent spiral contraction.)

(The spiral contraction which ensues after a tendril has caught a support is of high service to all all tendril-bearing plants; hence it is no doubt, thus its occurs no almost universally very generally in plants of widely different structure plants almost universal occurrence in with plants of widely different orders. When a tendril from an the a shoot is inclined, and it the tendril

[173v]

(a) The tendrils, however, of Eccremocarpus, which is allied to Bignonia contract spirally even when they have caught nothing. The uncaught tendrils of Mutisia & Cardiospermum rolls themselves up into a helix, like the tips of the leaves of the Gloriosa.

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proceeding from it, inclined shoot has caught an object above, the spiral contraction drags up the shoot.

Even When the shoot is upright, & the the & the its tendril has the growth of the internodes, subsequently to the the catching of the tendrils has tendrils having seized some object above, would slacken the stem & it would not ascent by the shortest course were it not for the spiral contraction, which lifts draws up each the higher internodes as it they increase in length. Thus there is no waste of growth & this stretched stem inwards is stretched & ascends by the shortest course. (B)

When a tendril has caught a yielding object, this is sometimes enveloped & still further secured by in the spiral folds, as I have seen with Passiflora quadrangularis; but this action is of little importance.)

(The highest A far more most important service is rendered by the spiral contraction, to the plant, is probably is that the tendrils are thus rendered made highly elastic.

As was previously remarked was when describing the under Ampelopsis, the strain is thus equally distributed to the several attached branches of a branched tendril; & this must

[174v]

(B) We have seen in the Cobæa, when a terminal branch of the tendril has caught a stick support, how well the successive spiral contraction of the its branches successively bring them one after the other into contact with the stick, until the whole tendril has grasped it in an inextricable knot.

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render the whole tendril in very much far stronger, as the same principle that a rope is stronger as branch after branch will can not separately break. It is this elasticity which prevent saves both branched & simple tendrils from being torn away into fragments during stormy weather. I have more than once gone on purpose during a gale to watch a Bryony growing in an exposed hedge, with its tendrils attached to thinner & thicker branches of the surrounding bushes; and as that thicker & thinner branches were loosed by to & fro by the wind gale wind, the attached tendrils, has they not been excessively elastic, would have instantly have been torn off & the plant thrown prostrate. As But as it was, the sight was a really interesting spectacle to watch the Bryony safely riding rode out the gale like a ship with two anchors down, & with a long range of cable ahead ahead, with much slack cable to serve serve as a spring, as she surges to the tempest storm.) We can now see, that when

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(With respect to the exciting cause of the spiral contraction, little can be said.

After reading Prof. Oliver's interesting paper* on the hygroscopic contraction of legumes, I allowed a number of different kinds of tendrils to dry slowly, but no spiral contraction ensued; nor did this occur with the tendrils of the Bryony when placed in water, diluted alcohol & syrup of sugar. so that We know that a tendril which has clapsed by its extremity some object, grows the act of clasping a support, leads to a change in the nature of the tissues of a tendrils, & so we must this a vital action; & call the spiral contraction this is all that can be said about we can at present say of the previous act of spiral contraction, which is consequent on the extremity of clasping a support. The contraction is in no way not related to the spontaneous revolving power, for it occurs in tendrils, such as those of Lathyrus grandiflorus, ampelopsis hederacea & Bignonia capreolata, which do not revolve.

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of their useful ends are served by the unaltered tendrils which have spontaneously wound themselves into a spire

* Transact. Linn. Soc. vol. XXIV 1864 p. 415.—

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(Tendril-Bearers)

(I have said that in Corydalis claviculata the end of the leaf or the tendril, for it may be indifferently thus designated, does not contract into a spirally. The branchlet, however, of the tendril after they have wound round their twigs became, deeply sinuous or zig-zag & this may be the first commencement indication of the process of spiral contraction. Moreover in which end of the petiole or tentacle, moreover, if it seizes nothing object bends abruptly downwards & inwards, showing that its inferior surface has contracted; & this may be more confidently looked at as the first commencement of spiral contraction.

For with all true tendrils, when they contract spirally it is the lower surface as Mohl (s. 52) has remarked, which contracts. If we suppose the inferior surface of the extremity of a free tendril to contract vigorously & quite replacing it would be rolled up into a flat helix as occur with a Cardiospermum; but if it were to contract in the last irregularly or if the tip were held, as if, as does occurs, the basal portion was to contract first, (as often does) at last surface so that which case the long free part could not be inclosed rolled up wither the basal convoluted part, or if the the tip as we shall see as in a second tendril caught bending some object the necess — in these cases is [illeg] result would will be the formation not of a helix but if a spire, such as free & caught tendrils form is the act of contraction.

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It is not necessarily related to the curling of the tips round a support, as we see with the Ampelopsis. Yet, it certainly seems to stand in some close relation to the the curling or clasping movement, due to contact with a support; for not only is it does it soon follow this act; but the spiral contraction generally begins close to the attached curled extremity of the tendrils tendrils & so & travels down towards to the base, as if the whole tendril tried to imitate the curling movement of its extremity. (a) It is the inner lower surface of the tendril which in both cases which contracts; the upper surface, as remarked by Mohl (s. 52) being forming the out outside of the tendril. spire.

With respect to The truly spiral contraction of tendrils which have not become attached to any objects, it is not to any object cannot only se serve any of the useful ends previously just described; it does not occur with comes on only after a long interval of time: it does not occur with many several kinds of tendril, which when attached contract; & when it does occur, it comes on, as we have seen, only after a considerable interval of

[177v]

(a) If, however, the tendril is be very slack, the whole length seem to become at first slightly flexuous almost simultaneously, at first flexuous, & then spiral.

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time. It may be almost likened to certain instinctive or habitual movements, performed by animals, when under circumstances rendering them manifestly useless;) like a squirrel scratching the floor of its cage & thus

(When an uncaught tendril contracts spirally the spire runs always runs in an uniform the same direction from tip to base. A tendril, on the other hand, which has caught an obj a support by its extremity, in invariably becomes twisted in one part in one direction & in another part in the opposite direction;─ the spires running turning in opposite course direction oppositely turned spiresbeing separated by short straight portions.

(Diagram 10 12) [Climbing plants, fig. 13,p. 165] 13 This curious & symmetrical appearance structure has been noticed by several botanists, but has not been explained.* It occurs without exception with all the tendrils, which contract spirally & which have been mentioned in this paper; & which even uses, after catching only any object contract spirally; but is of course conspicuous in the longer tendrils;

[178v]

* See M. Isid. Léon in

Bull. Soc. Bot. de France, Tom. V. 1858, p. 680. ─

(179

it never occurs with an uncaught tendrils; which has ultimately spirally contract: without occasionally, when and when this appears to have occurred, it will be found that the tendril had originally seized something some object & had then afterwards been torn away free.

The Commonly all the spires at one end of are attached a caught tendrils run in one direction & th all those at the other end in the other opposite direction, with a single very short straight portion in the middle but I have seen the spire in an a tendril from such straight bits with the spire alternately turning four five times in opposite directions with so many straight portions between them; & M. Léon has seem seven or eight such alternations. Whether the spires all turn alternately several times or only once in opposite directions; or all at one end if all are connected turning in which turn in the two directions; there are as many turns in the one direction as in the other.

For instance, I gathered ten long & long caught tendrils of the Bryony; one had some are with

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some are the longest with above 30 & one 33 & the shortest with only 8 spiral turns; & the number of turns in one direction was in every case, within one, the same in the two opposite sides of the the same (within one) as in the opposite direction.)

The explanation of this curious little fact is not difficult; but I will not attempt any geometrical reasoning it will explain as case by ca but will simply give only practical simple illustrations. When treating of spirally Twining plants I said I should have to come to. In doing this, I will shall have first explain allude to a point which was merely alluded to almost passed over when treating of Twining plants. If we hold in one left hand a bundle of parallel strings a young flexible sapling, or what is better a bundle of several parallel strings string There are several parallel strings together we can with our right hand suc turn them round & round & imitate the revolving movement of a Twining plant, & the sapling or strings do not become twisted. But if we now at the same time hold a stick in our left hand

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in such a position that by the same manner the strings are became spirally wound round it, it is a spire, they will be seen found to be ne inevitably to become twisted, & this is inevitable. Hence if a straight coloured line, was painted along the internodes of a twining plant, before it has spirally wound round a support, becomes twisted or spiral after it has so wound round. The stems yet The experiment was superfluous, had I painted a red line on the straight internodes of a Hop Humulus Mikania, Ceropegia convolu Convolvulus & Phaseolus, & saw it became twisted. It may be that as the plant wound round a stick. It is possible, but I have not seen a case, that the stems of some plants by spontaneously twining round on its their own axes, at the proper rate & in a proper direction, might avoid becoming twisted; but I have not seen no such a case.)

(In the above case illustration the parallel strings were wound round a stick; but this is by no means necessary, for if wound into a a hollow coil (as can be done with a long narrow

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slip of elastic paper) there is the same inevitable twisting of the axis. Hence when a tendril, which is free at its end or has caught nothing coils itself into a spire, it must either become twisted along its whole length, & this is a case which I have not never seen, or the free end extremity must turn round as many times round as there are there are spires are formed. It was hardly necessary to observe this; but I did so with the Echinocystis & Passiflora quadrangularis by affixing a little paper-vanes to the free & extreme points; & as the tendril under it contracted itself into successive spires, the little vane slowly revolved.)

(We can now understand the meaning of the spires being invariably turned in opposite directions, in the same tendrils when this it which have caught some object, & is are thus fixed at both ends. Let us suppose that a caught tendril contracted into 30 spires all were to make 30 spiral turns all in

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one direction; the inevitable consequence result would be that it would become twisted thirty times on its own axis. This twisting not only would require considerable force, but as I know by trial, would actually burst the tendril before the thirty turns were completed. (a) but as these are with caught tendrils. These are always always as many spiral turns in one direction as in the other; the twisting of the axis in the one direction is exactly compensated by that in the other. We can further see how the tendency is given to make coils to coil spirally in an opposite direction to those first coils made, whether these be to the right or to the left, which are first made. Take a piece of string & let it hang down with the lower end fixed to the floor; then wind the upper end, (holding the string quite loosely), spirally round a perpendicular pencil, & this will necessarily twist the lower part of the string; & after it has been sufficiently twisted, this lower part, of the strong necessarily it will be seen to curve itself into an open spire, with the curves running in an

[183v]

(a) Such a case never really occurs; for, as already stated, when a tendril has caught a support & has spirally contracted, there are always as many turns in one direction as in the other; so that

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opposite direction to those round the pencil, & consequently with a straight piece of string between the opposite spires. In short we have made given to the string the ordinary structure of ano regular spiral arrangement of a tendril caught at both ends. The spiral contraction generally begins at the extremity which has clasped a support & this, necessarily by the consequent twisting of the axis, support; & their first formed spires give a twist to the axis of the tendril, which th necessarily throws inclines the basal part of the tendril into spiral an opposite spiral curvature. I cannot resist giving one other illustration, it is so appropriate though superfluous: when a haberdasher winds up sew ribbon for a customer he does not wind it into a single coil; for if he did, the ribbon would twist wound itself as many times as there were coils; but he winds it into a figure of eight on his thumb & little finger, so that he alternately takes the turns in opposite directions, & then the ribbon is not twisted. So it is with tendrils, with this sloe difference, that they take several turns in one direction & then the same number in an opposite direction; but in both cases the self-twisting is equally avoided.)

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Summary on the nature & action of Tendrils.— In this concluding remarks, I shall have to allude to some points which will may be here passed over. In the majority of tendril-bearing genera observed by me, the young internodes revolve in more or less broad ellipses; like those of made by Twining plants; but the figures described, when carefully traced is generally form an irregular ellipsoidal spire. The rate of revolution in different plant varies from differs from the one to five hours; for each revolution, consequently is & consequently in some case is more rapid than the with movement of any twi twining plant, & is never so slow as in the with those many twining plant twiners which takes more than five hours for a each revolution. The direction is variable even in the same individual plant. (a) The Vine is the poorest poorest revolver, & apparently exhibiting only a trace or rudiment of a former power. In the Eccremocarpus there are the movement is interrupted by many long pauses. Some but very few tendril-bearing plants, such as some species of Bignonia, and, Paullinia (according to Mohl s. 4) & Passiflora gracilis. & Paullinia can spirally

[185v]

In the same genus, as in Passiflora, the internodes of one species may revolve, whilst they are motionless in other species.

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twine up an upright stick, but Though although the twining power is generally lost, though the revolving movement, apparently owing to from the stiffness or shortness of the internodes or the from the size of the leaves, or from any other unknown causes the revolving movement is retained & well serves to bring the tendrils into contact with surrounding objects.

(The Tendrils, themselves likewise revolve have the power of revolving in the same manner & generally & & at the same rate as the internodes, (a) In most cases both internodes & tendrils revolve harmoniously together; in other cases, (as in Cissus Cobæa) & most Passifloræ the tendrils alone revolve: in other case, (as in some Bignonia & Lathyrus aphaca) the internodes alone move, but not the carrying with them the motionless tendril: and lastly, (& this is the fourth possible case), neither ten internodes nor tendrils move spontaneously revolve, as with Lathyrus grandiflorus & the Ampelopsis. In most Bignonias, in the the Eccremocarpus, in addition to Mutisia, and Bignonia littoralis Fumariaceæ, the internodes & tendrils, the petioles of the leaves and the internodes all spontaneously revolve together.)

(The tendrils revolve by the curving curvature of this whole length, excepting the extremity & excepting

[186v]

(a) The movement begins whilst the tendril is young, but is at first slow: in

(a) In Bignonia littoralis, however, the the maturetendrils moved much slower than the internodes.

In all cases the conditions of life must be favourable for the perfect action of all any [illeg] in th Tendrils. Generally

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(Summary Tendrils)

the base which does not move or but little.

The movement is of the same nature, as that of the young revolving internodes. Hence when if a line be painted along that surface which at the time happens to be convex, if the line becomes first lateral & then concave, & ultimately again convex. This experiment can be tried only on the thicker tendrils, & such as those of the rise, anguswhich are not affected by a thin crust of dried paint. The extremities, however, of the tendrils, which are are generally so often slightly curved or hooked, does do not never reverse its their curvature; & in this respect differ much from the tip extremities of the shoots of Twining plants, which reverse the course not only more abruptly, then the though less than the basal parts. reverse this curvature or at least, become periodically straight, but curve more in a greater degree than the base lower portions of the f internodes parts lower portions of the revolving shoot.

Anyone who did not understand the nature of the spontaneous movement of the a tendril, would conclude, that as the internodes revolve & carry the tendrils, and as these are at the same time revolving, that

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the tendrils would necessarily travel more quickly quicker than the internodes, & thus get in advance of them, instead of both moving harmoniously harmoniously together. But in fact the tendril answers to the upper of the several revolving internodes of a Twining plant; with when several internodes revolving; together and in the former part of this Paper, it was explained how several internodes revolve move together by their whole length successively curving to all points of the compass.

There is, however in many cases, this unimportant unimportant difference that the curving or revolving curving tendril is separated from the curving internodes by a rigid petiole. There is another difference, namely that the summit of the shoot, bearing the young unformed immature tendrils, g generally project above the point from which the revolving tendril arises; but this shoot is generally thrown on one side so as to be out of the way of the revolutions which how to be swept right above the plant; when the terminal shoot is not sufficiently out of the way, the

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(Summary Tendrils)

tendril, as we have seen with the Echinocystis, as soon as it come to this obstacle point in its curving curving course, stiffens & straighten itself & rising up vertically upwards passes over the obstacle.)

(All tendrils are sensitive, but but in various degrees, to contact with a few any object, & curve towards the touched side. With several plants a single touch, so slight as only just to move the highly highly flexible tendril, suffices is enough to induce movem curvature. Passiflora gracilis has the most sensitive tendrils, which I have seen observed: a bit of platina wire 1/50th of a grain in weight, gently placed on the concave point caused caused it two tendrils to become hooked, as did, & this perhaps is a better proof of sensitiveness, a loop of soft thin cotton thread weighing 1/32th of a grain or nearly two milligrammes. With several the tendrils of several other plants, loops weighing 1/16th of a grain sufficed. With the ab The point of a tendril of the above Passiflora gracilis distinctly began to move in 25 seconds after a touch: Asa Gray saw movement in the tendrils of the Cucurbitaceous genus, Sicyos, in 30 seconds, with other plants a few The tendrils of some other plants, when lightly rubbed, moved in a few minutes;

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(Summary Tendrils)

minutes elapses. In the Corydalis there was so; in the Corydalis Dicentra in half-an-hour; in the Smilax in one hour & a quarter or a half; & in the Ampelopsis, which has the least sensitive tendrils Ampelopsis still more slowly, after several light rubbings After li has

The curling movement after a consequent a consequent on a single touch continues to increase for a considerable time, their courses, & in all cases after a few hours the tendril in all cases uncurls itself & is again ready for action.

When very light weight such as the 1/10 of a grain was suspended on several tendrils of several plants & caused & caused curvature, the stimulus was usually insufficient to cause a tendril them to curve, they seemed to become accustomed to so slight a stimulus, & straightened itself themselves, as if the loops had been removed. It makes no difference with, as far as I have seen, with what sort of object a tendril is touches, with the remarkable exception, in the case of the extremely sensitive tendrils of Passiflora gracilis & of the Echinocystis, of drops of water; & we can hardly avoid concluding hence we are led to infer that they have become habituated to showers of rain. Moreover the adjoining tendrils

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(Summary Tendrils)

of adjoining shoots or plant rarely catch each other as remarked we have seen under Echinocystis & the same Passiflora; though I have seen occur with the Bryony.

Tendrils which are have slightly curved or hooked or bowed extremities generally are sensitive only on the concave surface & for a & to urge t length from this tip; other tendrils, such as those of Cissus discolor the Cobæa (though furnished with minute horny hooks & those of Cissus discolor, are sensitive on all sides. He Hence the tendrils of this latter plant when when stimulated by a touch of touched with equal force on opposite sides, does not bend. (B) The lower or basal parts of most tendrils of many tendrils are either not at all sensitive or sensitive only to prolonged contact. Hence we see that the sensitiveness of tendrils is a localized capacity. (a) In Bignonia unguis & its allies, the main main petioles of the leaves, as well as their the tendrils alone they become are sensitive to contact.)

(Twining plants when they come into contact with a stick, [illeg] curl round it invariably in the direction of their revolving movement; but tendrils curl indifferently to either way side in accordance with the position of the stick and the side which is first touched.

[191v]

(B) In the Mutisia the two lower & two lateral surfaces are sensitive, but not the upper surface.

With branched tendrils, the several branches are endowed alike in sensitiveness. behave in a similar manner; but in the Hanburya the basi-lateral branch for a very good reason did not acquire its sensitiveness till long so same as nearly so soon [illeg] the main branch,

[191rv]

(a) It is quite independent of the power of spontaneously revolving. The curling of the terminal portion of the tendril from temporary contact a touch does not in the least interrupt the spontaneous revolving movement of the it's the lower parts.

[191vv]

It is pro probably perhaps confined to the terminal portion of

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(Summary Tendrils)

position of the stick & either that side the surface whenever first touched. & this position of the stick. The movements of tendrils are is much quicker & their grasps much firmer than with twining plants.

The clasping movement of the extremity of the tendril, I infer to be vermicular in its nature caterpillar-like apparently is not steady, but vermicular in its nature, as may be inferred from the curious manner in which the Echinocystis it managed to it slowly crawled round a smooth stick.) (As, with a rare a few exceptions tendrils spontaneously revolve, it may be asked why are they endowed with sensitiveness,─ why when they come into contact with a stick they do not spirally wind round it, like a Twining plant? In most cases they are so flexible & thin, that they when brought into contact with a stick, they would bend yield & [illeg] thus not stop arresting to revolving & would not arrest the revolving movement of the lower part; of the tendril or internodes would & thus be they & would thus be dragged away.

dragged part to stick onwards. Moreover; they would be thus dragged onwards & away from the stick. Moreover the sensitive extremities of the tendril have no no power of spontaneous movement revolving power & could curl round not by this means curl round any object.

[192a]

windy day. It is, however, possible that the slow movement of the basal & stiffer parts of certain tendrils, which wound round a sticks when placed in their course, may be analogous to that of twining plants, But I doubt I doubt this; but I hardly attended sufficiently to this point; & it would be difficult, perhaps

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(Summary Tendrils)

With twining plants, on the other hand, the extremity of the shoot spontaneously bends more than any other part, & this is of high importance for the ascent ascending power of the plant, as may be seen on a windy day. I suspect, however, that the lower basal & stiffer parts of some tendrils have the power of Twining like true twining plants twiner: at least I found that this part in the Echinocystis, & Cissus discolor & Passiflora quadrangularis was not sensitive to a rubbing rubbing, yet when coming into contact with a stick placed in its revolving course, after a time wound round it; but it is difficult, perhaps impossible, to distinguish between a movement due to extremely dull sensitiveness & requiring long contact, & that resulting from the spontaneous movement of the arrestment of the lower part of a tendril & the continued revolving movement of the terminal part of a tendril.)

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(Summary Tendrils)

(Tendrils, which are only three-fourth grown, & perhaps more when younger, but not whilst extremely young, have the power of revolving & are sensitive of grasping any object when touched. which they may touch.

These two powers capacities generally are common & fail at about the same period & fail when the tendril is full grown. But in the Cobæa & Passiflora punctata (I noticed that the tendrils had commenced revolving in a quite useless manner before they had become had become sensitive.

In the Echinocystis they retained for some their sensitiveness for some time after they had ceased revolving & had drooped downwards, when it was curling they if they did seized should seize any object, it they could be of little or no use in supporting the plant stem. It is a rare circumstance to be able thus to detect any imperfection or superfluity in tendrils, which are so admirably organised for the end formations which they have to perform; but we see that they are not always absolutely perfect, & it would be rash to assume that any existing tendril has reached the utmost limit of perfection.)

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(Summary Tendrils)

Some tendrils have their revolving motion accelerated or retarded, in moving to or from the light; others, as with the Pea, seem indifferent to its action; others move from the light to the dark, & this aids them in an important manner in finding a support. In Bignonia capreolata when the whole tendril bends from the light to the dark, like a banner from the wind. In the Cobæa & Eccremocarpus, the extremities alone twist & turn round themselves, so as to bring their finer branches & their hooks to into into into close contact with any to any open surface, or into any crevices dark crevices or holes holes. This movement latter movement is one of the most elegant & best-adapted movements exhibited by tendrils.)

A short time after a tendril (with sone rare exceptions) have has caught any object a support, they it contracts spirally; but the a manner of contraction & the services thus rendered several important advantages thus gained have been so lately discussed, that nothing here need here be repeated on the subject subject.

Again, soon afterwards, the tendrils tendrils soon after catching caught a support grow much stronger & thicker. Thicker & more sometimes durable in a wonderful degree; It is & it is a remarkable fact & this shows how much their internal tissues must change.

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(Summary Tendrils)

that, at least in rare cases, their internal structure stem is becomes greatly modified changed by this contact

Tendril which have caught no object nothing, (B)

two species of Bignonia soon disarticulate & drop off like leaves in auth autumn, but in all other cases simply wither shrunk, wither & drop of at an early period.)

(Anyone who did had not closely study the action of studied tendrils of many various kinds would probably have impressed that their action was would be uniform. This is the case with many kinds, of which the extremities simply curl round object of any various shapes or natures, substance, even glass, & of any moderate degree of thickness. But Bignonia shows is tha what diversity for action then may be in the the tendrils & within the same genus of even closely allied species. (a) In the first-described, unnamed Bignonia buxifolia the tendrils, in shape like a bird's foot, are of no service when the stem spirally ascends in a thin upright stick, but clasp in passing over entangled over inclined branches it they but they call well seize them any twig or branch lying beneath them; In B. unguis the similarly shaped tendrils act in a

[196v]

(a) (B) soon shrink and wither & drop off; but in the some species of Bignonia, they disarticulate & fall like leaves in autumn.)

(a) In all the young internodes vigorously revolve: in all the tendrils are sensitive to contact; & little else can be predicated if these in common.

(197

(Summary Tendrils)

; but when the stem spirally spirally ascends a somewhat thicker stick, a slight degree of sensitiveness & of the power of spontaneous movement in the petioles of the leaves are is brought into play by their slight power of power of spontaneous movement, & they wind round the stick. In B. unguis & Tweedyana the sensitiveness, as well as the power of movement in the petioles are is greatly augmented; & the tendri tendrils are thus wound round wound in an inextricable round manner round a thin upright stick; but the stem in consequence does not twine so well.

B. Tweedyana in addition emits aerial roots which adhere to the stick. In B. venusta the tendrils have become much elongated & have lost the bird's foot structure, & are converted into three-pronged grapnels; & then for the first now exhibit a conspicuous power of spontaneous movement: the petioles, however, have lost their sensitiveness. The stem spirally twines round an upright stick, & is aided in its ascent by the alternate tendrils

(198

(Summary Tendrils)

seizing it above, (a) In B. littoralis & Chamberlaynii the tendrils have a similar structure; these & the more sensitive petioles & the tendrils internodes all spontaneously revolve; but the stem, however, cannot spirally twine, but an upright stick is seized by both tendrils above: in B. littoralis when the tips of the three-pronged grapnel-like tendrils are developed into adhesive discs. B. speciosa speciosa & picta have similar powers of movement, & the stem likewise cannot spirally twine; the simple undivided unbranched tendril can bent seize, but after several trials, their transverse sticks; but they wind round them in a different manner from the ordinary tendrils of Leguminosa, Passifloraceæ &c; & they exhibit the strange & apparently useless habit of continually inserting their pointed ends into minute crevices & holes. In B. capreolata, the stem spirally twines in an imperfect manner: the much branched tendrils exhibit hardly

[198v]

(a) & then spirally contracting. In all the following species we have the tendril spirally contract after seizing any object.

(198A

(Summary Tendrils)

any power of spontaneous movement, but they turn in a conspicuous manner from the light to the dark; their hooked extremities, even whilst immature, will crawl into any crevice, or when mature will seize to finest fibre, & in either case develop adhesive discs, which have the power of env enveloping a number of fibres.)

(In the allied Eccremocarpus, the internodes, petioles & tendrils all spontaneously revolve; the much-branched tendrils resemble those of Bi Bignonia capreolata, but they do not turn from the light, & their bluntly hooked extremities which arrange themselves so neatly to any surface, do not form adhesive discs; & they act best when each extremity seizes a a weak bundle few thin leaves a culm of culm grasses, few thin leaves objects like the culms of a grass which are after some draw they afterwards draw together by their spiral contraction into a solid bundle. In the Cobæa, the tendrils alone revolve; these are divided into many fine branches, terminating in elegant sharp little double hooks, & the terminal branch which crawl into crevice & are turned by an excellently adapted

(199

(Summary Tendrils)

movement to any object that is seized. In the Ampelopsis, on the other hand, there is little or no power of spontaneous movement in any part: the branched tendrils, are but little sensitive to contact; they turn, however to the dark; this hooked extremities cannot seize a fine any very thin objects; they will not even clasp a stick unless in extreme need to a support; but they turn from the light to the dark, or to any opake body object & spreading out their branches in contact with any such f nearly flat object, the discs are developed. These can can adhere, by the secretion of some cement to a wall or even to a polished surface, & this is more than the discs of the Bignoniacapreolatacan effect.) the [text pasted over]

of an adhesive cement.─ (a) (Finally, it may be added that America, which so abounds with arboreal animals, as has lately been insisted on by Mr. Bates, likewise, according to Mohl & Palm, abound with climbing plants; & I can of the tendril─

[199v]

(The formation rapid growth of these adhesive discs, with their power of enveloping the finest fibres, in one of the most remarkable peculiarities in the structure & function of tendrils. We have seen that these are formed by two species of Bignonia & by Ampelopsis; and I hear from Dr. Hooker that Naudin has described a Cucurbitaceous genus, the extremities of the tendrils all adhere to are enlarged spread out like fingers & all adherent. The outgrowth of the disc, in the former genus is caused by the stimulus of contact, & in apparently analogous to the swelling of the inferior & clasping surface of the petiole of Clematis calycina, & to the swelling & indication of ordinary tendrils after they have seized any object. There is, however, this difference that in the case that the outgrowth of the discs is confined to the extremities of the tendrils, though as we have seen with Ampelopsis, it sometimes spreads spread a little way down the finer branches; & there in the more more important difference that an adhesive cement is secreted by them.)

[199a]

[note added in another hand:] (to come before p 200)

according to Naudin* by the Cuc genus ─ Peponopsis adhærens

Their development apparently in all case due to depends on the stimulus from contact with some object. It is not a little singular that thus far, so widely different as the B. V. & C. should all have one or two members with species bearing tendrils characterized with this same remarkable peculiarity.

By comparing the ordinary tendrils & petioles in the several climbing plant which have been described, we can trace most of the steps in the series, by which the adherent discs have been acquired: most tendrils, after they have clasped any object, rapidly increase in strength & thickness throughout their lengths; but some tendrils as in B. several species of (as with some certain species of Bignonia Venusta & Clavi & picta) whether caught wound round a support by their middle or end extremities, swell became enlarges became locally swell enlarge swollen at their points in a remarkable manner: the petiole of C.C. after clasping a sti twig became enlarged [illeg] of forms in their its under surface a cellular layer which closely fits the wood: with Hanburya & similar layer in developed & this secretes some an adhesive cement: from this the formation of such a layer to that of an adhesive disc, or localised enlargement, the step is very small. But thoroughly to understand to step gradation by which the discs have been developed, we ought to see meet with all

[199v]

the above mention steps, more especially the first stages in the secretion of a little re resinous cement, in the members of the same Family; & from what we have seen it is not very improbable that all may still occur exist in the Cucurbitaceæ.)

(200

(Summary Tendrils)

-bearing plants, examined by me, the most admirable constructed come from the magnificent grand continent;─ namely the several species of Bignonia, Eccremocarpus, Cobæa & Ampelopsis.)

(Part IV.─ Hook-climbers ─ Root-climbers ─ Concluding Remarks.)

(Hook-climbers. In my introductory remarks, I stated that besides the great classes of Twining plants with the subordinate division of leaf-climbers & tendril-bearers, there were hook & root-climbers.─ I mention the former here, only to say that with the few, which I have examined, such as namely Galium aparine, Rubus australis, & some climbing roses there is no spontaneous revolving movement. except irregularly indeed if they were the plant If indeed they possessed this power, & were capable of twining, such plants would be taken placed in another the previous great class; thus the Hop, which is a Twiner, has reflexed hooks has as large as those of the Galium; some other twiners have stiff reflexed hairs; Dipladenia has a circle of blunt spines at the bases of its leaves. one tendril-bearing plant alone as far as I have seen, viz

[201A]

(a) One of the most remarkable is the Marcgravia umbellata, which in the tropical forests of S. America, as I hear from Mr. Spruce, grows in an a curiously flattened manner against the the trunks of trees & here & there it putting forth claspers (roots), which adhere to the trunk & if slender completely embrace it: when it has climbed to the light, it sends out shoot free & rounded branches, clad with sharp-pointed leaves, wonderfully different in appearance from those borne by the cur stem as it long as adhere to the adherent stem stem, as long as it is adherent: this surprising difference in the leaves, I have also observed in a plant of M. dubia in my hothouse.

Root-climbers, as far as I have seen no spontaneous power of movement, not even the Ivy (Hedera helix) or in Ficus repens, & barbatus,

(201

(Hook & root-climbers)

Smilax aspera, is furnished with spines; Some few plants which apparently depend solely on thin hooks are excellent climber, as certain Palms in the New & Old Worlds. Even some of the climbing Roses will ascent the walls of a tall house, if covered with lattice a trellis: how this is effected I know not, for the young shoot of one such rose, bent in a during the when placed in a pot in a window, curved bent irregularly towards the light during the day & from it during the night, like any other plant: so that it is not easy to understand how the shoots can get get under a lattice a trellis close to the a wall.)

Root-climbers. A good many plants come under this class & are excellent climbers; but suffer disadvantage are forced to keep much in the shade. They have not no even the power of movement, not even, as fat as I could ascertain in the Ivy, or Hedera helix, Ficus repens & barbatus.

(202

(Root-climbers)

from the light to the dark. As previously stated the Hoya carnosa (Asclepiadaceæ) is a spiral twiner & can likewise adhere by rootlets (a)

The Tecoma radicans (Bignoniaceæ), which belongs to a great climbing group, is so closely allied to many species being spontaneously-revolving species, climbs by rootlets, but its young shoots apparently move about more than can be accounted for by the varying action of the varying light.

(I have not closely observed many root-climbers, but can give one curious fact. Ficus repens climbs up a wall just like Ivy; and when the young rootlets were made allowed made to press lightly on slips of glass, they emitted (& I observed this several times) after about a week's interval minute drops of clear slight fluid, not in the least milky like that from a wound. This fluid was slightly viscid, but could not be drawn out into threads; & it had the remarkable property of not drying. One drop about the size of half a pin's-head,

[202v]

(a) Even to a flat walls: the tendril-bearing BignoniaTweedyana likewise emits roots, which move half round & adhere to their sticks.

(203

(Root-climbers)

I slightly spread out, & scattered on it four or five some minute grains of silex sand. The slip was of glass was left exposed in an open a drawer, during remarkably hot & dry weather, & if the fluid had been water, it would certainly have dried in a few minutes; but it remained perfectly fluid, round closely surrounding the each grain of sand, during by by 128 days: how much longer it would have remained I cannot say. Some other rootlets were left in contact with the glass for about ten days or a for fortnight, & the drops of fluid secreted by them were now rather larger & so viscid that they could be drawn out into threads. Another group group of Some otherrootlets were left in contact during exactly 23 days, & these were firmly cemented to the glass. Hence we must infer may conclude that the rootlets first secrete a slightly viscid fluid, & that they subsequently absorb (for we have seen that the fluid will not dry by itself) the watery parts, & ultimately leave a cement. When the rootlets were torn from the glass, minute atoms of yellowish matter were left on it, which when we were partly dissolved by a drop of bisulphide of carbon was placed in & this extremely volatile fluid was

(203A

(Root-climbers)

then rendered by what it had dissolved very much less volatile.

(As the bisulphide of carbon has so strong a power of softening indurated caoutchouc, I placed I soaked in it during a short time many rootlets of this a plant which had in it, for various short period, & then soaking soaked those in water grown up a plaistered wall; In two sets of rootlets on the same branch, I found very many excessively extremely thin fibres threads of a transparent, not viscid, excessively elastic substance, precisely like caoutchouc: these threads at one end proceeded from the bark of the rootlet & at the other end were firmly attached to transparent particles of silex & other hard substances. There could be no mistakes in these observations; for I played with the threads for a long time drawing them out with very dissecting needles & letting them spring back, under was evidently strong power of the simple microscope. Yet as as I looked repeatedly at other rootless, similarly treated, & could never discover these elastic threads, I infer that the branch had probably been

(203A

(Root-climbers)

slightly moved from the wall at some critical period period whilst he fluid secreted from the rootlets was in the act of drying & of undergoing some chemical change changing its nature & probably of undergoing some chemical change by the absorption of its water parts. The genus Ficus abounds with caoutchouc, & from the facts here given we may probably infer that this substance at first in solution & ultimately modified into an unelastic cement by Ficus repens to cement its rootlets to any object which it may ascend. Whether most other plants, which climb by their rootlets, emit any cement I do not know; but the rootlets of the Ivy, placed against glass, hardly barely adhered to it, but yet secreted a little yellowish matter. The rootless of Marcgravia dubia, I need add, can adhere firmly to smooth painted wood.)

Vanilla aromatica emits long aerial roots, a foot in length, which point straight down to the ground. According to Mohl (s. 49), these crawl into crevices, & when they meet with a thin support, wind round it, like tendrils.

[203C

(Root-climbers)

my a pant which I kept was young was not healthy & did not form long roots, but on placing twigs in contact with three of them they certainly bent in the course of about a day a little to that side & adhered by their rootless to the stick; but then they but they did not turn round it & repursued their downward course. if these rootlets are really sensitive to contact & bend to the touched side; in this case the class of root-climbers in this instance case would blends into that of tendril-bearers. According to Mohl the rootless of certain species of Lycopodium like likewise act as tendrils.─)

(204

(Concluding Remarks)

Concluding Remarks.─ Plants become climbers in order, as it may be presumed, to reach the light & to expose a large surface of leaves to its action & to that of the free air. This is effected by climbers plants with wonderfully little expenditure of organized matter, in comparison with trees a large which have to support a load of heavy branches & leaves by a thick & woody massive trunk. Hence, no doubt, it arises that there are in all parts of the world in in all quarters of the world, (ex[illeg] & alpine) so many climbing plants belonging to so many different orders. These plants have been classed under three heads: firstly, hook-climbers, which are, at least in our temperate countries, the least efficient of all, and for they can could climb only when growing by in the midst of an entangled mass of vegetation.

Secondly, root-climbers, which can admirably are excellently adapted to ascend on naked faces of rock; when they climb trunks they are compelled to keep much

(205

(Concluding R.)

in the shade; for when they cannot pass from top most branch to branch & thus cover the whole tip of the tree summit of a tree, for their rootlets can adhere only by long-continued & close contact with a steady surface. Thirdly, the great class of spiral Twiners, with the subordinate divisions of leaf-climbers & Tendril-bearers, which together far exceeds in number & in perfection of mechanism all the climbers of the two previous classes. These plants can easily pass from branch to branch by their power of spontaneous revolving & of movement on by contact, can easily pass from branch to branch & securely ramble over a wide and wide, light bathed and sunny brightly illuminated sun-lighted surface. I have a

(I have classed com ranked Twiners, Leaf & Tendril-climbers together as subdivisions of one class because they graduate into each other, & become nearly all have the same remarkable power of spontaneous revolving. Does this gradation, it may be asked, mere indicate that one

(206

(Concluding Remarks)

plants belonging to one subdivision have during the lapse of time ages have passed or can pass, from one state to the other; or have has, for instance, a tendril-bearing plant assumed their its present structure without having previously existed under a different form as either a leaf-climber or a Twiner?

This enquiry cannot, of course, be positively answered, but it seems probable that the two l. plants, which now climb by their leaves or by tendrils are were primordially simple spiral Twiners. I infer this from the following considerations: Twining plants are not only much the most numerous, but they occur in many Families which possess no leaf-climbers or tendril-bearers; whilst on the other hand latter rarely occur these are but few cases of these latter structures occurring in Families, in which there are no known Twiners without being accompanied in the same Family by Twiners.

In the Leguminosæ, for instance, as everyone knows,

(207

(Concluding Remarks)

there are many tendril-bearers & simple Twiners: in the great tendril-bearing Family of Cucurbitaceæ, at least one genus the Hanburya Mexicana is a (as I hear from Dr. Hooker), is a spiral.

In the Passifloraceæ, I have not heard of a true Twiner, but the young internodes of Passiflora gracilis spontaneously curve exactly like those of a Twiner, as is the case in an imperfect manner with the internodes of the common Vine, which belongs to another tendril-bearing Family.─ analogous facts could be given with respect to Leaf-climbers.

So that at least some trace of the supposed primordial habit of twining is almost is always retained by both subdivisions, tendril-bearing groups of Plants.)

If we consider the class of Leaf-climbers alone, the ideas belief idea that they are were primordially Twiners is forcibly brought to mind suggested. Some few of these are still actually good The internodes of all without exception revolve in exactly the same manner as Twiners; & some few

(208

 (Concluding R.)

can still twine well, & many others in a more or less imperfect manner. as has been previously described. (a)It should be particularly observed, that the possession of leaves with their petioles or tips of the leaves, which are sensitive & have with the consequent power of clasping any object, could be of very little use to a plant, unless accompanied by the revolving associated with revolving internodes, by which means they are brought into contact with surrounding ob support objects: on the other hand, the revolving internodes by without other aid cause suffice to give the power of climbing; so that unless we suppose both that leaf-climbers resembling it seems by f acquire not this power most probable that all leaf-climbers they were at first simple spiral- twiners & subsequently acquired gained their more complex sensitiveness & power of clasping why this additional aid shd be given to any spiral [illeg] will be presently considered.

[208v]

(a) Several leaf-climbing genera are closely allied to plants other genera which are simple Twiners.

(209

(Concluding R.)

climbing; so that unless we suppose that leaf-climbers simultaneously acquired both their powers capacities, it seems probable that they were at were at first revolvers acquired that of revolving which by itself would make them climbers & be of be of high service to them, & revolvers & could thus climb and subsequently that of became capable of grasping a support; which, as we shall see, is a great additional advantage.)

why this additional power should have been given them will be immediately considered.

(From analogous reasons it is perhaps in some degree probable that tendril-bearing plant were primordially Twiners,─ that is are descended from that that is, are the descendants of plants having this power & habit. For is the majority the yo internodes revolve exactly like those of Twining plants & in a very few the flexible stems yet retains the po capacity of spirally twining round an ste upright stick & in with other this revolving power has been lost by the internodes & has passed into the tendrils, & Tendril-bearing These plants have undergone much more

(210

(Concluding R.)

modification those Leaf-climbers; hence it is not surprising that their supposed primordial revolving & twining habit has been is more frequenting lost or modified. The thin great tendril-bearing (a)

(On the view here given, it may be asked why have some or nearly all the plants or at least some of them in in so many groups of aboriginally Twining groups Twisting plants group which are aboriginally Twiners been converted into leaf-climbers or tendril-bearer? or leaf-climbers? Of which advantage could this have been to them? why did they they not remain simple Twiners continue to climb by simply twining? remain simple Twiners? We can see several reasons. (B) Anyone who will look at a Twining plants during windy weather with we see also discover how that they are easily they are blown from their support; for they adhere simply by the arrestment; not so with tendril-bearing or leaf-climbers for they quickly & firmly grasp their support by a very widely different & superior much more efficient kind of

[210v]

(B) It might, perhaps be an advantage to a plant to have acquire a thicker stem, with short internodes bearing many or large leaves; & this such a stem would be ill fitted for twining. but it will be clear evident to anyone who will look during windy weather at Twining plants

[210v2]

(a) Families in which this loss has occurred in the most marked manner, are firstly the Cucurbitaceæ, Passifloraceæ & Vitaceæ. In the first, the internodes revolve, but this is in I have heard of no Twining forms, with the exception of more (according to Palm s. 29, 52) of Momordica balsamina & this is only an imperfect Twiner. In the other two families I can hear of no Twiners & the internodes rarely have the power of revolving, this power being confined to the tendrils; nevertheless the internodes of Passiflora gracilis revolve well, as do have this power in a perfect in degree & manner & those of the common Vine in an imperfect degree manner degree. So that at least a trace of the supposed primordial habit is always retained by ten some members of all the larger tendril-bearing groups.)

(211

 (Concluding R.)

movement. In those plants, which still twine, but at the same time use their possess tendrils or sensitive petioles, as with some of the species of Bignonia Clematis & Tropæolum, we can readily see observe how incomparably more securely they hold to an upright stick than do simple Twiners. (a) Tendril-bearers can can from their first growth ascent along by the outer twig of the surrounding bushes thus be always in sun-shine; whereas Twiners generally start in the shade branches of any neighbouring bush & thus always keep always in the sun-shine full light: twiners on the contrary are best fitted to ascend bare stems & generally have to start in the shade. In denser Tropical forests, with crowded & bare stems, twining plant would probably succeed better than most most kinds of tendril-bearers; but as far as I have seen but the majority of twiners, from the nature of their revolving movement, cannot ascend a thick stem trunk; whereas this can be

[211v]

& thin, so that little organic matter is expanded in their development, & yet they can sweep a wide circle.

[211v]

From possessing the power of movement on contact, tendrils can be made very long & thin so as to expand little organic matter & yet sweep a wide circle.

(212

(Concluding R.)

Effected by tendril-bearers, if the trunks has very a good many branches or twigs left; & in some cases they can ascend by spiral means a trunk without branches but with rugged bark, even if destitute The object of all climbing plants apparently is to reach the light & free air with as little expenditure of organic matter as possible: now with plant spirally ascending the stems plants, the stem is much longer than is absolutely necessary; for instance I measured the stem of a kidney-bean, which had ascended [illeg]exactly two feet in height & it was three feet in length: the stem of pea, ascending by its tendrils, would on the other hand have been but little longer than the height which it had gained height which was gained.

That this saving of stem is really an advantage to climbing plants I infer, from observing that those that still twine, but are aided by clasping petioles or tendrils, generally

(213

(Concluding R.)

make a more open spires than those made by simple twiners. Moreover, such plants very generally, as was observed over & over again with the several leaf-climbers, after taking one or two turns in one direction, run for a space straight & then reverse the direction of their spire. By this means they ascend to a remark considerably greater height with the same length of stem than would otherwise have been possible; & they do this with safely safety as they are secured to their the support secure themselves at intervals by their clasping petioles.─

We have seen that tendrils consist of various modified organs in a modified state namely leaves, perhaps stipules, branches & flower-peduncles, perhaps branches & stipules. The position alone after gen generally suffices to show when a tendril has been formed from a leaf; & in Bignonia the lower leaves are often

(214

(Concluding R.)

perfect, whilst the upper ones present a tendril in the place of the medial terminal leaflet: in Eccremocarpus I have seen a lateral branch of a tendril replaced by a perfect leaflet; & in Vicia sativa, on the other hand, leaflets are some way down the leaf replaced by tendril-branches; a branch of a tendril branch: & many other such cases could be given.

Position alone suffices to show that other tendrils are modified branches or flower-peduncles; but we have other facts, such as those given under the vine, which leave no doubts on this subject point head. But he But he, who believes in the slow modification of species will not be content simply to knowing by simply ascertaining the homological nature of different tendrils; he will wish wishes to learn as far as possible, by what, steps leave organs parts acting as leaves, or as flower-peduncles can have entirely wholly changed their functions, & now have come to serve simply as prehensile organs.)

(215

(Concluding R.)

(With respect to leaves, (We have seen in the whole group of leaf-climbers abundant evidence that are organ still acting ssubserving subserving its proper end function of a leaf may become sensitive to a touch & thus be lead to grasp an adjoining object; it the petiole then grows thicker & stronger. In some several other leaf-climbers, the true true leaves spontaneously revolve. The petioles of the leaves after clasping a support grow thicker & stronger. Thus we have see in their true leaves have acquired may acquire all the leading & remarkable characteristics of tendrils, namely sensitiveness, spontaneous movement & subsequent thickening & indurative induration. If the sensitive parts of the leaves were their blades of same or laminæ had the aborted were to abort, they would be from truest tendrils.

And of this process of abortion we have seen every stage. In an ordinary tendril, as if in that of the pea, we can discover no trace of its primordial nature. In Mutisia clematis the tendril in shape & colour & closely resembles a the petiole with the midribs of the leaflets, & occasionally a vestiges of laminæ are retained or reappear. And lastly In Corydalis claviculata on the same individual plant, some few of

[215]

[addendum]

And of this process of abortion we have seen every stage. In an ordinary tendril, as if in that of the pea, we can discover no trace of its primordial nature. In Mutisia clematis the tendril in shape & colour & closely resembles a the petiole with the midribs of the leaflets, & occasionally a vestiges of laminæ are retained or reappear. And lastly In Corydalis claviculata on the same individual plant, some few of the leaves terminate in true tendrils, whilst

[215v]

[page scored]

(a) In The lateral branches of the tendrils of Mutisia clematis we see the petioles & midribs of the leaflets, retaining still retain the appearance & structure of the midribs of the leaflets, & are sometimes bordered by narrow green laminæ, of which a vestige is always present.─

(216

(Concluding R.)

others are furnished with leaflets reduced to almost microscopical size; so that it is scarcely possible to know decide whether the plant sh ought to be classed as a leaf-climber or tendril-bearer.

In the Gloriosa Lily the terminal & produced part portions of the leaves, when the plant has grown to some height, are denuded of laminæ & act as tendrils. Finally in Tropæolum tricolorum we have another kind of passage, for the leaves which are first formed on the young shoot, are entirely destitute of laminæ, & must be called tendrils)

(On the view here given, leaf-climbers were primordially Twiners; & those tendrils-bearers (of the modified leaf group division) were primordially leaf-climbers. Hence the latter ought to latter ought to be closely related stand between Twiners & Tendril-bearers, & ought to be related to both.

[216]

[addendum]

(of the

primordially leaf-climbers. Hence the latter ought to latter ought to be closely related stand between Twiners & Tendril-bearers, & ought to be related to both.

This is the case: thus the several leaf-climbing genera of species members of the Antirrhineæ, of Solanum, of Cocculus, of Gloriosa all related to other genera in the same Family, or even to other species of in the same genus, which are true Twiners.

On the other hand the leaf-climbing species of Clematis are very closely allied

(217

(Concluding R.)

to the tendril-bearing Naravelia; so are same leaf-climbing forms of species of the Fumariaceæ include closely allied genera which are leaf-climbers & tendril bearers. Lastly the genus one species of Bignonia includes is a both a leaf-climber & a tendril-bearer, & Twiners closely allied species are twiners & tendril-bearers.

(Tendrils of another great division consist of modified flower-peduncles, as can be told from their position on the plant. In case likewise we have many interesting transitional states. The common vine (not to mention the Cardiospermum) gives us every possible grade between simple & from grandly developed true tendril leaving [illeg] usual & the single to a bunch of flower-buds, bearing the single usual lateral flower-tendril. And when this flower-tendril the latter itself bears some flower buds flowers, as we know is not very rarely the case, & yet still retains its power of clasping a support, we see, the primordial condition state

[217]

[addendum]

know is not very rarely the case, & yet still retains its power of clasping a support, we see, the primordial condition state of all those tendrils which consist of have been formed by the modification of the flower-peduncles. *a)

[217v]

[not transcribed]

(218

(Concluding Remarks)

(According to Mohl & others some tendrils consist of modified branches. I have not seen now, & no such cases & therefore of course know nothing of the any transitional states, if such occur.

But Lophospermum at least shows its branch below the that such a transition could be affected is possible; for the its branches of the plant spontaneously revolve & are sensitive to contact. Hence if the leaves on some of the branches were to abort, they would possess the true characteristics of be converted into true tendrils. Nor is it so improbable, as it at first seems, appears that certain branches alone should become modified, the others remaining unaltered; for we have seen with certain varieties of Phaseolus, that some of the branches revolve are thin & flexible & twine, whilst other branches on the same plant are stiff & have no such power.)

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(If we enquire still further back, & ask how a petiole of a leaf or the peduncle of a flower or a branch first became sensitive & acquired the power of moving bending towards the touched side, we get no distinct certain answer. Nevertheless an observation by Hofmeister*a well deserves attention, namely that the shoots & leaves of most all plants, whilst young, move after being shaken; & it is almost invariable the young petioles of leaf-climbers & the young tendrils, of climbing whether formed of modified leaves or flower-peduncles, which move on being touched; so that it would appear as if these plants had utilised & perfected a

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sensitive to contact & bends to a touched side & yet does not at least in the plant observed by me, even not a true actually climb a support or not as like true tendril a like a petiole of a leaf-climber─

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widely-distributed & incipient capacity, If which capacity, as far as we can see, is of no service to ordinary plants. If we further inquire how the stems, petioles, tendrils, & flower-peduncles of climbing plants first acquired their power of spontaneously revolving, or to speak more accurately of successively bending to all points of the compass, we are are again silenced;─ or at most can only remark, that the power of movement, when of any use to plant both spontaneously & from various stimulants, is far more common with plants, as we shall presently see, than is generally supposed by those who have not attended to the subject. We have, however, this (a)

(There is one remarkable interesting point which deserves notice attention notice. We have seen that some tendrils have originated from modified leaves & are other foliar in l from modified flower-peduncles; so that some are foliar & others axial in their homological nature. Hence it might have been expected that they would have presented some differences in function.

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(a) one remarkable case of the Maurandia semperflorens, in which the young flower-peduncles spontaneously revolved in very small circles, & bent themselves when gently rubbed to the touched side; yet this plant certainly made profited in no way by these two feebly developed powers. A rigorous examination of other young plants would might probably show slight spontaneous movements in the peduncles & leaves, as well as sensitiveness to shaking observed by Hofmeister. Anyhow we see in the Maurandia a plant which might by a very little augmentation of equalities, which it now already possesses, come first to grasp a support by its flower-peduncles, (as with the vine or Cardiospermum) & then by the abortion of its some of the itsflowers acquire tru perfect tendrils.)

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This is not the case. On the contrary they present the most complete identity in their several peculiar remark remarkable characteristics.

Tendrils of both kinds spontaneously revolve at about the same rate. Both when touched bend quickly to the touched side; & afterwards recover themselves & can act again. In both the sensitiveness is either confined to one side or extends all round the tendril. Tendri

They are either attracted by the light or bend from it. The latter We see this latter fact in the foliar tendrils of Bignonia capreolata & in the axial tendrils of Ampelopsis. The extremities tips of the tendrils in these two plants become, after contact, enlarged into adhesi discs, which are at first adhesive by the secretion of some resinous cement.

Tendrils of both kinds, soon after grasping

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a support contract spirally; they then increase greatly in in thickness & strength. When we add to these several points of identity the fact that the clasped petiole of Solanum jasminoides, assuming when at the characteristics woody ring of woody vessels characteristic features of the axis, namely a closed ring of woody vessels, we can hardly avoid asking, whether the difference between foliar & axial organs can be of so fundamental a nature as is generally supposed to be the case.)

(We have attempted to trace some of the stages in the genesis of climbing plants. But during the endless fluctuations of the conditions of life to which all organic beings are subjected exposed, it might be expected that some climbing plants would have lost this habit. In the curious cases given by certain South African plants, belonging to great climbing Families,

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which in their certain districts of their native arid country never climb, but we assume by reason, this habit, when cultivated here, we have a case in point. In the leaf-climbingClematis flammula, & in the tendril-bearing Vine we see no loss in the power of climbing, but apparently the last trace only feeble a remnant of the revolving power which is so we indispensable with to all Twiners, & so is so common as well as so advantageous with to most climbers. (a) with respect to tendrils, In my limited experience, I have not with only one clear instance of their natural loss advance abortion suppression namely in the common bean.

Excepting this one All the other species of Vicia all the others, I believe, of the genus have tendrils; & in but the bean which is stiff enough to support its own stem, & in this plant species, at the end of the petiole, where another a tendril ought to have arisen, a small pointed filament may be seen is always present, about a third of an inch in length, & which must must

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(a) In Tecoma radicans, one of the Bignoniaceæ, we have see in see a last & doubtful traces of the power of revolving p power. With respect to tendrils, certain cultivated varieties of Cucurbita pepo according to Naudin* (a a) have either quite lost these organs or bear semi-monstrous representatives of them.

* (a) (a) Annales des Sc. Nat. 4th series, Bot. Tom 6. 1856, p. 31.

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be considered as the rudiment of the tendril. This can may be the more safely concluded inferred, because I have seen in young, healthy specimens plants, not growing ha true tendrils bearing species plants which do n similar rudiments. In the Bean there vary are variable in shape, as as in so general frequently the case with all rudimentary organs. parts), being in shape being either cylindrical, or foliaceous, or deeply furrowed at on the upper surface. & pointed at the tip. It is rather a curious little fact that many of these filaments when foliaceous have a black secretary dark-coloured glands on their lower side surfaces, like thos those on the stipules which secrete a sweet fluid; so that the rudiment have been feebly utilised.)

(One other analogous case, though hypothetical, is worth giving. Most of the Nearly all the species of Lathyrus possess tendrils, but L. nissolia is destitute of them. This plant has leaves, which must have

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struck every one who has noticed them with surprise, for they are quite unlike those of all common papilionaceous plants & resemble those of a grass. Now In Lathyrus aphaca, the simple unbrnahced tendril, which is not highly developed for it is unbranched & has no power of spontaneous revolving power, replaces the leaves, the latter in function being replaced by the large stipules. Now if we suppose the tendrils of L. aphaca to become flattened & foliaceous, like the little rudimentary tendrils of the bean, we should & the large stipules not being any longer at the waited to become at the same time reduced in size, same time to decrease smaller, we should have the exact counterpart of L. nissolia; & its curious leaves became are at once rendered intelligible to us..)

(It It may be added, as it will serve to sum up the foregoing the views on the origin of tendril-bearing plants, that if these

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view are be correct, Lathyrus nissolia must have descended primordially from a spirally Twining plant; that this became a leaf-climber; that first part some of the leaf & then the whole leaf became converted into a tendril, when the leaves disappeared & were replaced by tendrils; this became with the stipules by compensation greatly increased in size* that this tendril lost its branches & become simple & then lost first this its revolving power, (a) ; that they then become lost their prehensile power & becoming foliaceous were no longer tendrils. In this last stage they reassumed their original function of a leaf, & their its lately largely developed stipules being no longer wanted decreased would decrease in size. if it be true that species change become modified in the course of time ages, we may safely conclude that Lathyrus nissolia is the result of some such some a a long series of modification changes such as here here just been traced.)

(The most interesting point in the natural history of climbing plants is their various diverse

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(note)

* Moquin-Tandon (Eléments de Tératologie. 1841, p. 156) gives the case of a monstrous bean, in which a their compensation of this nature was effected at a blow; for the leaves had completely disappeared & the stipules had grown to an enormous size.

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a/ (in which state it would resemble that of the existing L. aphaca); and afterwards lost losing its prehensile power & becoming foliaceous would no longer be called a tendril. In the last stage, (that of the existing L. nissolia) the former tendril would reassume its

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powers of diverse movement; & this led me on to their study. them. The must different organs, ─ the stems, flower-peduncle, petiole, mid-rib of the leaf or leaflets & apparently aerial roots,─ all possess these powers.)

(In the first place, the tendrils, for instance in the Cobæa, place itself in the proper place themselves in the proper position for action, standing, for instance to the Cobæa, vertically upwards with their branches divergent & their hooks turned outwards, & with the young terminal shoot thrown on one side. Or, as in Clematis, the young leaves temporarily curve themselves downwards so as to serve as a grapnels.)

Secondly;─ but the following movements is common common to nearly all plants of if the young shoot be bent down placed in an inclined position, it soon bends upwards, though placed in complete darkness. though completely secluded from the light. The guiding stimulus to their movement is the attraction of gravity, as Andrew

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showed be the case with germinating plants.

So it If a succulent shoot of almost any plant be placed, in an inclined position in a glass of water in the dark, the tip will in a few hours turn bend upwards; & if the position of the shoot be then now reversed, the motion will again now now downward bent shoot will reverse into curvature; but if the directions of the curvature is not invariably if the stolon of a strawberry be thus treated, which has no tendency to grow upwards, be thus treated it will curve downwards in the direction of, instead of in opposition to the force force of gravity of gravity; so it is with the climbing shoots of the twining Hibbertia dentata, which wishes to climbs laterally from bush to bush; the & its for these shoots when bent downwards downward bent shoots show show little & sometimes no pull tendency to curve upwards.)

Thirdly, climbing plants move towards the light by a movement closely analogous to that success incurvation, which changing its direction

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causes them to revolve. This was well seen when a climbing plants had been had been kept in a room during the night & its their first movements from the morning were traced first towards the light & then in a revolving course were traced on a bell-glass. We have also seen that the movement of the revolving shoots & in some cases of the tendrils all retarded & or accelerated in run travelling from or to the light. In a few case instances tendrils move little in a conspicuous manner from the light. Some Many authors speak as if the movement of a plant towards the light was were was as directly the result of the evaporation or the oxygenation of the sap in the stem, as, the movement elongation of a bar of iron from increased temperature.

But it seeing that tendrils move to or from are either attenuated or repulsed repelled by the action of light, it more is more probable that their movements are only guided by stimulus by its action, in the same manner

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as they are guided by the force of attenuation from or towards the centre of gravity. Fourthly; we have in the stems, petioles, flower-peduncles & tendrils of all kinds the spontaneous revolving stimulus, but is contingent on the growth of the organs part & on their its vigorous health, which again of course depends on a proper temperature & other conditions of life.

This is perhaps the most interesting of all the movements of climbing plants, because though it is continuous. Very many other plants exhibit spontaneous movement; yet but they generally occur only once during the life of the part as in the movements of the stamen & pistils &c, or at in long intervals of time as in the so-called sleep of plants.)

Whereas the revolving movement is continuous; a the nearest approach to this is perhaps the movements of the leaves in the Hedysarum

Fifthly; we have in the tendrils, whatever their homological nature may be, in the petioles &

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tips of the leaves of leaf-climbers, in the stems in one case & apparently in the aerial roots of the aerial roots of the vanilla, movements, often rapid movements, from contact with any body. Extremely slight weight pressure generally suffices to cause this movement. The parts after temporary contact became straight again & can again in bend on contact when touched.)

Sixthly & Lastly:─ most tendrils soon after clasping a support, but not after a more temporary curvature, contract spirally. The stimulus from the act of clasping seems to travel slowly down the whole length of the tendril.

Many tendrils, moreover, ultimately contract spirally contract spontaneously even if they have caught no objects; but this useless latter useless movement occurs only after the a considerable lapse of time.)

(We thus see how diversified are the movements are of climbing plants. They These plants are so numerous as to form a conspicuous feature in the vegetable kingdom; everyone has heard that this is the case in Tropical

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(Concluding Remarks)

forests, but even in in the thickets of our temperate regions the number of individuals & of kinds is considerable, as will be found by counting them. They belong to many & widely different orders. To gain some crude idea of their distribution in the vegetable series, I marked all the from the lists given by Mohl & Palm (adding a few myself, & a competent botanist no doubt could have added add many more) all the Families in "Lindley' Vegetable Kingdom", which including which include any plant that climb by spontaneously revolving, & whether or not they be aided by tendrils in one more class in any of our several sub-divisions of Twiners, leaf-climbers & tendril-bearers; which implies that & those namely all have and there (at least some in each group) all have the power of spontaneously revolving. Lindley divides phanerogamic plants into 59 alliances, of these no less then above half, namely 35, include climbing plants according to the above definition; so that hook- & root-climbers are being excluded.

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To these, a few cryptogamic plants must be added, which climb by revolving. When we reflect on this wide serial distribution in the older series grand of plants having this power; & when we know that in some of the largest & well-defined orders, such as the Compositæ, Rubiaceæ, Scrophulariaceæ, Liliaceæ, &c., two or three genera in each alone out of the host of genera [illeg]in each, have this power, the conclusion is forced on our minds that the capacity of acquiring that revolving the revolving power of revolving on which climbing depends most climbers of this class depend, is inherent, though undeveloped, in almost every plant in the vegetable kingdom.

It has often been vaguely asserted that plants are distinguished from animals by not having the power of movement. It should rather be said that plants can always

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a display acquire acquire & display this interact power, only when it can be is of any some advantage to them; but this is of completely rare occurrence, as they are affixed to the ground, & food is brought to them by the wind & rain. (a) To sum up, let Let us look at one of the more highly organised tendril-bearing climbers. It first places its tendrils in the right position ready for action, as a polypus arranges places its tentacula.

If the tendril be displaced, it first is acted on (I know not what other & more correct term to use) by the force of gravity & rights itself. It feels is acted on by the light, & bends towards or from it or disregards it, whichever may be most advantageous. During several days the tendril or shoot internodes, or both, spontaneously revolve with a steady motion.

When by this movement, the some object

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(a) Sometimes they display movement, as with the Hedysarum &c, of which we cannot see any utility. The perfection of the organisation of plants is forced on our minds by the study of the many kinds that climb.

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(Concluding Remarks)

The tendril strikes some object, & quickly curls round & firmly grasps it. In the course of a few some hours, it contracts itself into a symmetrical spire, & forming an excellent spring contract [text pasted over]

All movements now cease. But

By growth, the tissues of the tendril soon become wonderfully strong & durable. so as to last long after The tendril has now now now done its work, & done it in an admirable manner.)