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Final results of all exper. in Lythrum to end of 1865

On the character of the progeny from the illegitimate unions in of dimorphic & trimorphic species of plants; together with some remarks on Hybridity

by

Ch. Darwin

I have observe various plants, which I have called reciprocally dimorphic & having now seen Union In papers read before this Society. I have described several plants which I have called reciprocally dimorphic & trimorphic.

[Insertion:]It may be common belief to ask what is meant by these terms.

In their dimorphic plant one form has a long pistil & short stamens; & the other long stamens & a short pistil, & in order to be fully fertile the two forms must reciprocally fertilise each other & this I have called a heteromorphic union. each pistil by it On the other hand when either form is fertilised by its own-form pollen the fertility is more or l diminished or completely destroyed. sterility ensues, & this has been called a homomorphic union. But from the subsequent discovery of the th trimorphic condition of Lythrum it will be has been found more convenient

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Lythrum 1865

to speak of the union of each form with its own-form pollen as illegitimate, & the progeny from such union as illegitimate. On the other hand the uni reciprocal union between the two forms, in which the pistil of the one form generally is of the same equals in length as the stamens in the other form, may be spoken of as well as the progeny as legitimate. & is fully fertile, & the progeny as legitimate.

In the trimorphic species of Lythrum we have a more complex case; for there are three forms having pistils of very different lengths, & each form bears two sets of stamens differing in length & in other respects. Hence, as I have shown in my paper on Lythrum salicaria,* within the limits of this one species eighteen unions now can be made, of which six, between pistils & stamens of equal lengths are legitimate & fully fertile, & twelve are illegitimate & more or less sterile.

It occurred to me that it would be worth while to raise plants from seed from the illegitimate unions of dimorphic &

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Lythrum 1865

trimorphic species plants & carefully observe their character. I have not been disappointed in thinking this well worth observation. I shall give the results in considerable detail, partly because the undertaking has been laborious,─ the mere counting of the seed in Lythrum, being no slight work, for above 15000 had to be were counted during one season under the microscope ─ but chiefly because more light is thus indirectly thrown by these observations on the [illeg] sterility of the hybrid offspring of from distinct species, than by any other facts with which I am acquainted.

I will begin with Lythrum salicaria.

Some of the illegitimate seedlings were observe & experimented on in 1863, but rather too late in the season. In 1864 many others were observed, but summer & sun the plants were rather too young &c summer was very hot & dry so that some the fertility of some few of the legitimate plants growing close by was affected; & although the plants were copiously watered, I shall trust little to these observations, except in a few cases.

[3v]  

Ly. sali is a trimorphic species

I shall give the results of my experi on the fact of the illegitimate offspring from the illegitimate ones of several lowest & doing sp a full detail ─ because

I note common with Lyth Sali which is a trimorphic plant, but I did not succeed did not succeed in raising seedlings from all, the 18 same for only 7 6 of pods 7 of the 12 perfect illegitimate one.

There are The experi will be arranged in classes, according to their parentage of the plants x. I shd presume that when the certain plants were allowed to be freely crossed by insects, the finest pods were selected, in order to [illeg] over [illeg] the result so that the average firstly is probably always will higher than in stating correct. [illeg] to [fertility] of the Lythrum is [illeg] influence by the season, which is & for that reasonmy observation has been extended over several years. x (In each case I give the average production of seed stating [5 words illeg]; I state the maximum, which is in [6 words illeg]

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Lythrum 1865

in which the fertility was complete, even under their somewhat showing that they had not been affected by these unfavourable circumstances.

In 1865 many good observations were made; as in 1866. From one of the illegitimate (a)

(As this lessened fertilityIn order to judge of the fertility of the form illegitimate seedlings plant is one the their chief characters, I must give of a little statement will seem as a standard of comparison, the average & of the maximum fertility of the three forms of the the legitimate ordinary or legitimateplants when legitimately & freely fertilised by insects, will seem as a standard of comparison which can only be referred to.

[4v]

(a) unions was obtained produced; & from some others the few seed did not germinate; so that the character of all the illegitimate unions could not be observed.)

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Lythrum 1865

This table can be referred to for comparison with in all the following cases ─ for comparing as a standard for the fertility of all the illegitimate plants. With these latter I have given the minimum as all as the maximum number of seed observed, that it may be seen between what extremes the average has been struck. In almost every most cases the seed & the best very good capsules were collected in ten capsules has been counted to obtain the an average; & this I believe is sufficient. In three cases I in which the seeds of fifteen capsules were counted, for trial I struck out for trial the two highest & two lowest numbers, & the remaining nine gave the same average within one or two seeds, as the whole fifteen.

Class I

Illegitimate seedlings plants from long-styled plants parents fertilised by their own-from pollen.

From this union I raised at different times during successive years from three same lot of seedlings parent plants….. [2 words illeg] to 56 plants seedlings. I must premise that from not forming the result, I do not need average [3 words illeg] I do not know whether their a [illeg] which the first lot of 8 plants were raised from seed, which had been fertilised by the longer or shorter stamen of the same form, the But I [5 words illeg]

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Lythrum 1865

plants were fertilised by pollen from their own form longer or shorter stamens; & their two kinds of pollen in this form differ essentially in power; but I suspect that the first lot of eight seedlings which differ in some respect from the others are the product of the shorter stamens, & the others remainder I feel almost sure are the product of the pollen of the longer stamens, & this latter is a more fertile union.

(The whole of All the 56 plants in the 3 lots proved to be are long-styled; whereas had but if these parent plants been illegitimately fertilised by pollen from the longer stamen of the short- or mid-styled forms, only about one-third alone of the seedlings would have been long-styled, & the other two-thirds would have been short- & mid-styled. plant In [illeg] of crumple & damage plant green, in Under Primula we shall [illeg] found, the same [illeg] & [illeg] fert, namely the small size with abundant evidence of the curious & [illeg] fact that long-styled forms in evergreen fertilised by their own pollen reproduce only all exclusively or abort exclusively long-styled seedlings.

None of these 58 plants ever grew to their proper height & size (a). The first lot of 8 plants

[6v]

(a)

; as could be plainly seen for they grew in rows in the same soil close along side of the other several illegitimate & legitimate plants.

But it is not [many words illeg]

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Lythrum 1865

of eight were dwarfs, not being more than half as tall as they should be. (a) Most of them also flowered later in life & rather later in the season than do legitimate plants: & one plant in an unprecedented manner did not flower till full three years old. In G 2 other lots. In many of the plants of all three lots, some of the anthers, were either shrivelled or contained brown pulpy matter: they were, what Gärtner has called contabescent; but to this subject I shall towards close of the paper recur. I did not & in exam the days hardly of observed the degree of fertility power of seed-production of plant of the own present parentage the first lot of eight & ─ of the remainder, under the following circumstances. as I will need detail

No. 1.

I. Long-styled plant (1 my number), was grown quite isolated, excepting a brother seedling No II, so that they it could be fertilised only by their its own-form pollen, & this plant it did not produce during three two years a single capsule during the year 1865. A legitimate long-styled plant, as I have shown in my previous paper on Lythrum, thus similarly treated was

[7v]

(a) & they plainly betrayed in their whole appearance a very weak constitution.

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Lythrum 1865

covered with capsules, & each contained on an average 25 21.5 seed. This same plant during 1863 was allowed to flower with a moderately fertile several many illegitimate mid-styled plant of all two forms standing close by, & yet it did not produce a capsule, so that it is apparently absolutely & completely sterile.

II. Long-styled plant (my no. 2.) grown by with no. I prod is a shade less sterile, for it yielded one year twenty-two two capsules, fifteen of which the best fifteen were examined. Only seven of these contained any seed, namely on an average three very poor seed each; but the seed were so poor that i do not believe suppose one could have germinated. During 1866 which was a favourable year it did not produce one capsule. During 1863 it was allowed to flower together with legitimate plants of all three forms; but it even then yielded fewer capsules with but a slightly larger average of rather better seed.

(III, & IV V (my numbers 3, 4 & 10) Long-styled plants, all as miserably sterile as no. II. when allowed to flower, during 1863, together with other at the same time with another form of other a mid-styled illegitimate plant. (a) During 1864 & 1865, no

V. Long-styled plant (my no 10) had exposed during 1863 like the two last at the same period produced only four capsules, which altogether contained only five seed. During 1864 & 1865 & 1866, the latter being a favourable year for the seedling of other plants growing in the same bed it was allowed to flower at the same time with many legitimate & illegitimate plants of all three forms, but it yielded not a single capsule. Twelve flowers were likewise artificially fertilised

[text excised] legitimate mid-styled

[8bis]

forms, but it yielded not a single capsule.

Twelve flowers were likewise artificially fertilised by the proper pollen of a legitimate mid-styled capsule & not one set. Hence this plant is almost as absolutely sterile as no, I.)

[8v]

(a) no. V. produced altogether only four capsules with any seed, which altogether contained only five seed!

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Lythrum 1865

VI. Long-styled plant (my no. 4.) During 1863 this plant was a little more fertile than any of its brothers. during 1865 it was allowed to flower well surrounded by several illegitimate plants of all three forms (some of which as we shall see are moderately fertile) descended from self-fertilised parents short-styled & mid-styled plants fertilised by their own-form pollen & some of which these as we shall see are moderately fertile. Under these circumstances ten capsules yielded it produced a good many capsules; ten of which yielded an average of 36.1 seed; 47 being the with a maximum of 47 (ie percent & a minimum number of 22. (a) Hence this plant is a good yields not nearly half the number of seed, which a legitimate plant produces, when thus similarly freely fertilised by the legitimate plants of the other two forms.

(Thes The plants hitherto described all belong to the first lot of eight, I examined carefully only two plants three of the remainder of the same parentage remaining plants of similar descent, namely from long-styled plants parents by their own-form pollen, probably from their longer stamens. These illegitimate plants are not so dwarf or so sterile as those of the first lot. of the

[9v]

(a) During 1864. this plant was allowed to be freely fertilised by the surrounding legitimate plant of both all forms, and nine capsules (one poor one being rejected) yielded an average of 41.9 seed, with a maximum of 56 & minimum of 28.

In the second lot of plant, described from a long-styled plant, almost fertilise by its own pollen, & almost certainly from the longer stamen, the plants was were as almost [illeg] not nearly so dwarfed or stunted as those of the four lot.

I counted the number of seed in examined carefully only 3 plants. All produce plenty of capsules, & I counted the number of seed in every of the illegitimate plants, viz VIII, IX & X

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Lythrum 1865

(VII. IX Long-styled plants (my no 125 107), was allowed in 1865 to be freely fertilised by illegitimate plants from mid-styled & short-styled parents by their own pollen, & yielded an average from fifteen capsules of 57.1 seed with a maximum of 86 & minimum of 23. Hence this plant is no attains the rather above half the normal fertility.)

(VIII. X Long-styled plant (my no 125), similarly treated with the last & at the same period, yielded from ten of capsules an average of 44.2 seed, with a maximum of 69 & minimum of 25. Hence this plant does not attain half the normal fertility.)

(IX. VIII Begin with this Long-styled plant (my no 108), allowed during the hot summer of 1864 to be freely fertilised by legitimate plant of both all forms, yielded from ten capsules, an average of 41.1 seed, with a maximum of 73 & minimum of 11.

These extreme numbers were are so connected that it was impossible to reject any the poorest capsules in striking the average. Hence this plant like the last does not attain half the normal fertility.

p 4

The plants were in so in most cases left to be freely & legitimately fertilised through the agency of bees; by other illegitimate or legitimate plants of both for belonging to the two other forms. In this case the full & normal complement of seed ought to have been produced.

The fairest trial in order to ascertain the effect of illegitimate [illeg] infertility the production [few words illeg] is when both the pollen-producing, as well as seed-producing parents are of illegitimate [illeg] both; but in many several cases (which as always stated) the plants were exposed so as to be fertilised by legitimate from pollen by from legitimate parent plant of the other two forms; & this ought to have increased their fertility [illeg]would favour their fertility. it is always stated

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Lythrum 1865

Class II

(Illegitimate plants from a the short-styled parent form, fertilised by its own-formpollen from the shorter stamens of the same form.)

X. (I raised nine plants, & eight of which were [fused] short-styled and one long-styled; so that there seems a strong; but not an invariabletendency as with the long-styled plant are invariable tendency to reproduce for this form when self-fertilised to reproduce only its own the parent form. alone These nine plants never attained the full height of legitimate plants with many of them plants some of the anthers were contabescent. & contained no good pollen.

X. Short-styled plant (my no 16), during 1865, when allowed to be freely & legitimately fertilised by illegitimate plants descended from self-fertilisation mid-styled & long-styled parents by their own-formed pollen, it from of fifteen capsules yielded from an average of 28.3, seed, with a maximum of 51 & minimum of 11 & fert (these extreme numbers being were connected by [illeg]manysmall steps. The seeds themselves were small & irregular in shape. Hence this plant attained produced only 33 per cent of the normal number of seed to about one-third of the normal fertility of short-styled plants, when legitimately fertilised, I may add that this plant, though so little fertilise in its female organs had differently from many other of the same parentage, all its anthers perfect.—

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Lythrum 1865

(XI. Short-styled plant (my no 20) treated like the last, during the same year yielded an average from fifteen capsules of 27.0 seed, with a maximum of 49 & minimum of 7. But two poor pods may be rejected, & then the average from twelve capsules rises to 32.6 with a maximum of 49 & minimum of 20. So that this plant all probably attain the 38 per cent of the norm fertility rather above one-third of it's the normal fertility, & is consequently rather more fertile than the last, yet many of its anthers were contabescent.

(XII. Short-styled plant (my no 15). We have seen in the excessively sterile plant of the first lot of eight from a long-styled parent by its own-form pollen, that one plant was considerably mor less sterile than the others. Here we have a plant almost of the same parentage as the last two & treated in exactly the same manner during the same period, almost or perhaps perfectly fertile: for th ten capsules yielded an average of 77.8 seed (ie 94 per cent of the full [illeg]) with a maximum of 97 & a minimum of 60. By7 referring to the standard of comparison, it will be seen that the normal fertility of the short-styled form is 83.5 seed with an observed maximum of 112.)

[12v]

[calculations not transcribed]

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Lythrum 1865

(XIII. This the one Long-style of the same parentage as the two last, exposed so as to be freely & legitimately fertilised by the same two other illegitimate forms as in the former cases descended from self-fertilised parents, this plant yielded an average, from ten capsules, of 76.3 rather poor seed with a maximum of 88 & minimum of 57. So that this plant attains produced barely 82 per cent of its proper number of seed four-fifths of the normal fertility. Twelve flowers were artificially & legitimately fertilised under a net by the proper pollen from a legitimate short-styled plant, & nine capsules yielded an average of 82.5 seed with maximum of 98 & minimum of 51. So that the good capsule pollen from it probably was increased by the action of legitimate plant pollen; increased its fertility, but still it did not more rise up to the full normal standard.

Class III

(Illegitimate plants from lo mid-styled parents fertilised by pollen from their own-pollen form pollen) from the longer stamens of the same forms.)

I succeeded of the trials in raising only from plants from the same in two lots. These were proved to be three mid-styled & one long-styled forms; but so t from such so few small a number a number we cannot hardly judge of the tendency of transmission of form from self-fertilised mid-styled parents plants, but the facts do not contradict the conclusion drawn from self-fertilised short-styled parents to reproduce its own form.

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Lythrum 1865

These four plants did not never attained the full normal normal height. The one long-styled plant had several of its anthers contabescent.)

(XIV. This mid-styled plant (my no 11) were [illeg] freely fertilised in 1865 by the other the illegitimate forms plants descended from self-fertilised long & short styles parents yielded an average, from ten capsules of 102.6 seed, with a maximum of 131 & minimum of 63. So that this plant does did not great produce [illeg] 80 per cent of the normal number of seed. attains to about four-fifths of its normal fertility. Twelve flowers were artificially & legitimately fertilised by proper pollen from a legitimate long-styled plant & produced nine capsules with an average of 116.1 seed, which were finer than those in in the former case previous case seeds, with a maximum of 135 & minimum of 75. so that legitimate pollen, as in the cases of plant [illeg] nor XIII XVI, increased the fertility of the plant but yet did did not bring it up to the full standard complement.

(XV. mid-styled plant (my no 7) freely fertilised at same period & in the same manner & at the same period as the last, yielded an average from ten capsules of 73.4 seed with a maximum of 87 & minimum of 64. Hence this plant does not attains produce two three-fifth only 56 per cent of of the normal fertility full number of seed. Thirteen flowers were artificially & legitimately fertilised by proper pollen from a legitimate long-styled plant, & yielded ten

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Lythrum 1865

capsules with an average of 95.6 seed; so that the application of legitimate pollen from a legit plant, as in the two previous pl cases, added to the it's the fertility of this illegitimate plant, but did not bring it up to the full standard.)

(XVI. The Long-styled plant, of same parentage as the two last mid-styled plants, freely & freely fertilised in the same manner as with two last cases, during 1865, by pollen of the t other illegitimate forms descended from self-fertilised parents, yielded on average, from ten capsules, of 69.6 with a maximum of 83 & minimum of 52. Hence this plant, which had some of its anther contabescent, attains produced 75 per cent of the full number of seed, to rather above two-thirds of the normal fertility.)

(Of the twelve illegitimate unions which can be made, between the pistils & pollen from stamens of a six are between each form with its own two sets of anthers, & such all the plants as I succeeded in raising from them unions have now been described.

There remains six other illegitimate unions between the pistil of each form & pollen from one set of stamens of not corresponding height in the

[15v]

six other illegitimate unions are possible, nearly between each form & pollen the set of stamens in both the other two two forms which do not correspond in height with its pistil. But I succeeded in raising plant from only those of a union. in the plant class From one of them, forming the great class, the plants were raised. These counted      & not in [illeg]

Each form can be illeg. fertilised by pollen from one set of stamen in the other 2 forms, so that 6 additional illegitimate unions are possible; but I succeeded in raising plant from only 3 of these unions. In one of them, forming the parent class, 12 plants were raised, & these counted of

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Lythrum 1865

other two other forms. I raised three lots of such illegitimate progeny which are not to be described.

Class IV.

(Illegitimate plants froma short-styled parent fertilisedby pollen from the longer stamen of the long-styled form.)

I raised twelve plants from this union; & of eight proved to be short-styled, from long-styled plants, & set one mid-styled. These plants hardly attained to their full & proper height, but by no means described to be called dwarfs. The anthers in some of them were contabescent.)

(XVIL. Short-styled plant (my no 25), freely fertilised during 1865), by all all these the illegitimate forms, descended from self-fertilised long-, mid- & short-styled parents, yielded on average, from ten capsules, of 43.0 seed, with a maximum of 63 & minimum of 26

 Hence this plant barely exceeds 52 per cent half the normal fertility. This plant was remarkable from all the anthers of the longer stamens & some few of those on the shorter stamens being contabescent. (over)

[16v]

In one plant observed the scarcely more than half to normal number of seed was produced; a second was slightly sterile; a third, from & f. 1st was actually more fertile than my yielded more seed than the standard.

This may be partly accounted for by fine capsules being barely been always selected in order to arrive over estimating the degree of infertility of the several illegitimate plants, & partly by the season 1865 & 1866 having been extremely favourable; but I have am driven to believe that the 3 plants were abnormally fertile; It is possible that the standard number may be too low, but this is not likely, as the seed from 25 capsules of legitimate plants legitimately fertilise, both naturally & artificially, were counted.

It shd also, be observed, that if the standard is too low, the plants which have been shown to be sterile, must be looked considered as sterile in a still higher degree.

[71]

Lythrum 1866

XIX

Plant. 30 long-sty, from short sty plant see p. 16. from by long stamens of long-styled, freely fertilised & legitimately, 8 pollen of 3 others all forms of this same lot & lot from mid-styled by pollen of stamen short stamens of long-styled; so fertilised by other illegitimate plants all others having been cut down. Season too late in early part & not very favourable.─ (Pollen in both sets good, they [illeg] did not swell.)

73. [+] 68 [+] 67.x [+] 78 [+] 120x [+] 70 [+] 74 [+] 104 [=] average 82.0

XVIII

Plant 27 short-styled, same parentage as above 30. During 1866 see p 17 see above how crosses by vis by Plants, no 30, 31, 33, 75, 79, 82, 94. ─ Pollen of both sets perfectly seed

123. max [+] 102 [+] 89 [+] 102 [+] 91 [+] 86 min [+] 111 [+] 100  [=] 804 [÷] 8 [=] 100.5 average (121.1 per cent)

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Lythrum 1865

Pollen of both anthers perfectly seed

(XVIII. Short-styled plant (my no 27) exposed allowed during the hot summer of 1864, which was plainly unfavourable to the fertility of several of the plants, to be freely & legitimately fertilised by the other legitimate plants, yielded an average from eight capsules, of no less than 104.2 seed, with a maximum of 125 & minimum of 90. During 1866 over 100 so that we have here the singular fact of this an illegitimate plants in proportion of 125 to 100 considerably exceeding under apparently unfavourable circumstances, both in its average & maximum seed-production, any legitimate plant observed by me; whilst its brother illegitimate illegitimate short-styled form (no XVII) is only produced only half its full complement of seed & had many of its anthers contabescent.)

(Plant 31.)

(XIX. Long-styled plant (my no 30) of the same parentage as the two last, & exposed to fertilisation at the same time & in the same manner (59 per cent) as the last, yielded an average from ten capsules, of 55.0 seed, with a maximum of 88 & minimum of 24 in 1866 88 per cent. Hence this plant attained to rather above half the normal standard of fertility.)

During 1866 – only 82

Plant 33 ─ 131 per cent

p. 17A

Plant 31─ short-styled ─ same parentage as last 1866

Pollen perfectly good on both anthers average from f six eight Pods 111.5!!! 113.5

wonderfully fertile (83: 113. : : 100 : 136 per cent)

122. [+] 123. max [+] 119 [+] 93 min [+] 100 [+] 112 [=]  669 [÷] 6

669 [+] 120 [+] 119 [=] 908 [÷]8 [=] 113.5

Plant 33 long-styled same parentage as last (1866) average from 8 pods 122.5 seed per pod!!!

It is evident that 1866 most favourable season for seeding.

N.B. all each kind of cross "Class I." Class II.

The long-styled by own pollen will be Class I. Designate each experiment as Plant number 1, 2, 3, 4, 5. (88 per cent of normal production)

103. [+] max. 149 [+] min. 84 [+] 124 [+] 114 [+] 133 [+] 142 [+] 131 [=] 980 [÷] 8

[in margin, in blue pencil] a moderate amt of pollen from short styled

[17Av]

[Calculation not transcribed]

These plants exposed to plants of Class IV. & V all 3 forms freely crossed by Insects very favourable year.

18

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Lythrum 1865

Class V

(Illegitimate plants from a mid-styled parent, fertilised by pollen from the shorter stamens of the long-styled form.─)

I raised 25 plants from the [illeg] which turned out proved to be short-styled, & 17 long-styled with not one short-styled. (When we compare this result with that from the last illegitimate union, (viz from a short-styled parent fertilised by pollen from the longer stamens of long-styled form) we see in both cases, with the 37 plants, that they have inherited the form of either parents, but do have not produced a single plant of the third form, which assuredly would have been the case with a much fewer number of plants raised from any legitimate union.─) None of these 25 plants from our present union are was in the least not at all dwarfed. & are less sterile than most of those hitherto described. This result according with the degree of fertility of the union between the two parents; for

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Lythrum 1865

the a legitimate mid-styled form when fertilised by pollen from the shorter stamens of the long-styled form yield far more seed (viz an average above all poor capsules are rejected of 60.2 of 47.4 seed per capsule, as given in my former paper on Lythrum) than do any of the illegitimate progeny from the unions hitherto here described. After 1866 I shall have to consider whether any of the others shd be introduced.

XX. mid-styled plant (my no 75), when allowed to be freely fertilised during the hot summer of 1864 64.2 per cent by its brother seedlings & by neighbouring legitimate plants, yielded an average, from ten capsules, of 83.5 seed, with a maximum of 110 & minimum of 64. Hence this plant attained the rather above three-fifths of its normal fertility

XXI. mid-styled plant (my no 77) fertilised in same manner & at the same time as the last, its brother-seedling, yielded an average, from then capsules of 99.4 seed with a maximum of 122 & minimum of 53. Hence this plant attained the nearly four-fifths of its normal fertility 76. per cent

Plant 82 mid-sized 100 per cent

20

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Lythrum 1865

(XXII. Long-styled plant (my no 79) of same parentage with & fertilised in the same manner as the two last, yielded an average, from ten capsules, of 84.6 seed with a maximum of 132 & minimum of 47. Hence this plant attained the nearly above eight-ninth ninth-tenth of the normal fertility (during 1866 107  54 per cent 91 per cent

Plant 94 long-styled 98 per cent 101 per cent

(XXIII. Long-styled plant (my no 78) of the same parentage as the three last. Twelve Some flowers were legitimately fertilised by pollen from the longer stamens of one of its brother a short mid-styled seedling, nor XX, & produced nine five capsules, containing on an average 90.6 seed with a maximum of 97 & minimum of 79. So that apparently, as far as five capsules serves, this plant attains 97.9 very nearly its full normal fertility. (This same plant allowed to be freely fertilised during 1864 yielded only from 10 capsules ⸮ an average of 49.6 with max. of 69 & min. of ⸮ 36: but this lessened fertility, I presume, may be attributed to hot summer.)

[calculations not transcribed] (: : 100 : x = 54 per cent)

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Lythrum 1865

Class VI.

Illegitimate plants from a mid-styled plant fertilised by pollen from the longer stamens of a short-styled form.─)

I have shown in my previous former paper of L. salicaria that the union, whence these illegitimate plants were raised derived, is far more fertile than any of the all the other illegitimate union unions thus fertilised for the parent mid-styled parent when yielded an average of (all poor pods being rejected) 102.8 seed, instead of the normal number of 130, with  a and the character of the illegitimate progeny in the class according with this but slightly lessened fertility of the parent-union; I raised 40 plants for these plant are not were very hugely vigorous & considerable [illeg]attained their full height & was covered [3 words illeg] not in the least dwarfed.

I observed no contabescent anthers. The fertility of the two plants, above which were carefully observed is not, as shown below impaired. and lastly we have in the product of this one illegitimate union all three forms appear: I raised 40 41 seedlings [Insertion:] It deserves particular notice that the 40 plants differently from which occur in any previous case, included all the forms& these turned out 8 mid-styled taking after the mother-forms; 18

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Lythrum 1865

short-styled after the father & 14 long-styled; and neither parent in long-styled taking after neither parents, but in according with the usual law of production of legitimate seedlings.

(XXIV. Mid=styled plant (my no 44) allowed to be freely fertilised, during the hot summer of 1864 by its brother seedlings & by other legitimate forms, yielded an average from eight capsules, of 127.2 seed with a maximum of 144 & minimum of 96. This degree of fertility approaches so closely to the normal standard that the plant, especially as the summer was unfavourable, may be considered as perfectly fertile.)

(XXV. short-styled plant, (my no 46) of same parentage & treated in the same manner as the last, yield an average from ten capsules, of 113.9 seed, with a maximum of 137 & minimum of 90. Hence this plant, like one previous one nor. XVIII, attains a much higher degree of fertility which when I have never ever observed with any number legitimate plant!)

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Lythrum 1865

(Summary on the illegitimatecharacter of the progeny from the several illegitimate unions between the three forms of Lythrum.)

We find in the      illegitimate plants now described all grades of fertility, from the utter & hopeless sterility, in which even when fertilised by pollen from legitimate plant an empty capsule was not produced, to complete fertility & in two cases to a degree of fertility which as far as my experience has gone goes, is abnormal. Amongst the seedlings from the same union, sown at the same time & treated alike in every way, the degree of sterility varies much; but there are bounds to this variability, for on the one hand the most sterile occur in the brother classes [illeg] in which are generally the greater number of plants are the least fertile; & on the other hand the most fertile occur in the lot which are generally the least sterile. My materials do not permit me to compare in each case the degree of sterility of the first illegitimate union between 2 long style 3

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reference to the general result of all my experiments in all 6 classes, it deserves especial notice that if my the standards are erroneous in being too low; that the sterility of all the many sterile plants is really a would be increased in exactly the same proportion. [illeg]greater than appear in the Table results percentage column in the Table.

(The last point which need here be noticed is that as far as my means of

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the legitimate legitimate parent with that of the illegitimate progeny; but a certain degree of parallelism certainly holds good, for the offspring from those unions which yield a fair amount of seed are themselves far less sterile than the offspring from the more sterile variant, namely from each form with by its own-form pollen, yet most sterile of all seedling legit. I raised not most sterile.

Both sexual elements are affected in these illegitimate plant: this was plainly seen in the male element in the contabescent anthers being contabescent in so in many of the plants. In regard to the female element, as judged of by the sev production of seed, most of the plants were allowed to be freely fertilised, by the insects by the proper kind of pollen derived from other illegitimate plants; so that it might be thought that the lessened number of seed was exclusively caused by the application of inferior pollen.

3?

 

(3?

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Lythrum 1865

But this cannot be maintained, for several plants were allowed to be freely fertilised & others were artificially fertilised by legitimate plants pollen & nevertheless did not yield a full complement of seed; & others were artificially fertilised with both kinds of pollen &; though, as we have seen. The good pollen generally increased the number of seed produced.) yet it did not raise it to the full standard.

(There is also some degree parallelism amount of accordance between the degree of sterility of the illegitimate plants & their degree of dwarfing; for the first & much the most sterile lot of eight are much the most dwarfed, & the least less sterile lots & the last lot which apparently in no degree sterile are not at all dwarfed.)

(Lastly In the last place there is some we have the singular fact of the 56 plants, produced from the long-styled form, were fertilised by its own pollen from its own longer fruit same form reproducing

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Lythrum 1865

Dr Holland first called attention to this fact subject in the case of P. …. & to state hereafter fully find it abundantly [2 words illeg]

Exclusively long-styled offspring alone;— if the mid & short-styled forms fertilised by their own pollen reproducing preponderance of the mother-form;— & if the mid- & short-styled forms when fertilised by the stamens of mon-corresponding height of the long-styled forms, not producing all three three forms, but only the two parent forms. In one & the last lot of plants; lot alone which are not at descended from a union which is very little sterile, & which the plants themselves are being not sterile & not dwarfed, all three forms are reproduced as from say legitimate union. any as in the case of a [illeg] ordinary ora legitimate union

(At the end of this paper it will be shown how strikingly most of the fact here summed up characters observed in their illegitimate plants, produced by the union, improper union of distinct the three forms of the same species are paralleled by hybrid plant produced by the improper unions of distinct species.

(All Used)

[26v]

From the results observed by sowing seed which had been naturally produced of the plant, & from the three forms occurring in approximately equal number in the wild state, can have every reason to believe that all three each of the forms, when legitimately fertilised ordinarily reproduce all three forms. Now in about equal numbers now we

32 plants in the six classes were subjected to various trials, & the seed carefully counted.

The is a wide divide in fertility in the plant of the S. fert classes, & in the not same plant been its

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In class 4, 5 6 — look at first no sterility First prove sterility — but this was very firstly believe error — [illeg] & not of full height — Doubt about standard. remember in do. Abnoraml fertility — season.

The last point which needs here be noticed

Lastly (p. 24) parallelism believe 1s union & offspring — Parallel but doubt sterility I have already remarked that pollen from legitimate plant, as observe in 3 or 4 cases add a little to fertility

The values of three concluding remarks will be here at [illeg] of paper, p. 26 — when we compare the illegitimate plants, the hybrids under make the [illeg] of the same species — with true hybrids made between distinct species.