[63]

Cucurbita ovifera Heel

(The Cucurb. must require to expose their Cots. as soon as possible to Light so as to assimilate.)

Dec. 15th 8° 30' a.m.

2 seeds laid flat, with radicle perpendicularly bent down .35 inch in length from tip of seed-coats have heel on lower side only a just perceptible transverse prominence about 1/10 of inch within apex of coats. In Tips of coats removed above & below marked with 2 tall pins.—

Dec. 16' 8° 30'. a.m. In the above 2 seeds heel now largely developed— Development wonderfully sudden— i.e in 24 hr.

Now examined 28 seeds laid flat on peat & covered by peat & in every one heel developed on lower side. In every one, except one case, the heel (which is flat on lower side & sloping on upper side) had caught tip of seed coats & arched hypocotyl was bursting open the seed-coats. I have seldom seen anything more pretty. [sketches]

I feel almost certain that seed must lie on one flat & natural side on ground for heel to act; for if f seed placed vertically as at B. hypocotyl & radicle will protrude in same line & apex or ridge of heel, (instead of flat lower side) will come into contact with tips of seed-coats & scrape over them, instead of splitting the coats open.

Begin by saying if seed not planted in natural position, but vertically apparatus will not act— showing coordinated adaptation.

Dec. 17th 8° a.m.— 9 seeds were buried with flat side vertical & longer axis horizontal [sketch] & in all these cases heel formed on lower side transversely to flat side of seed (∴ add 9 to above 18 seeds showing action of geotropism) Of the 9 4/9 freed themselves from their seed coats & 5/9 retained seed-coats after rising above Peat.— The heel would have rubbed slightly against both edge of orifice of Coats, instead of flat lower side side resting on lower lip of orifice.

(over)

[63v]

17th 9° a.m continued) 3 seeds placed with perpendicularly with radicle end downwards & both all 3 have risen with seeds coats on. 1 seed placed with radicle end upwards & this came up with seed coats on.

19th 1 with end of seed coats removed & has come up with seed-coats on.

1 with do do…with seed-coats shed.—

19th 15 laid flat, all have come up naked, except 2 doubtful as yet for still partially buried— peat excessively loose so very unfavorable for forming seed-coats. —

(21st Altogether 18 seeds were laid flat on natural position on peat & covered with layer & 17 of these came up above the friable peat with skins cast off.)

(Dec. 21 soaked in Permanganate 25 more radicles — Heel somewhat variable in form & size— grow at generally stained on edge, as well as beneath — occasionally narrow zone on upper surface — (say nothing about 2 knobs) I have seen secondary radicles developed from lower surface & 1 such radicle from upper surface

29 [+] 13 [=] 41

Flahault says heel belongs wholly to hypocotyl, but tested by permanganate of potash, which colour radicle, but not hypocotyl brown the lower flat surface of heel p is a part of the radicle & upper sloping side part of Hypocotyl— 8 seedlings were thus tested in 1 of the cases half if the whole heel was tinted brown, so that in this case more than the lower surface of heel belonged to radicle.—

[64]

Jun 22d 1879— The arching of the Hypocotyl, is not in the lest least due to geotropism, at least in Cucurbita ovifera. — for when seed pinned through cotyledons within seed horizontally to cork & kept in darkness over water, or in water, the base upper part of radicle radicle or base of hypocotyl is lifted up in opposition to geotropism, & the arch formed in usual manner — it is due to epinasty— (Though as we know apogeotropism soon soon comes into play & raises both sides of arch arch into vertical position. N.B The closure or arching of the a many hypocotyls of many seeds pinned in various positions on the cork, was in opposition to geotropism, & must be due to epinasty, for light was excluded.

[65]

Fig 61. Cucurbita ovifera [sketch]

Fac-simile: the heel-like projection rests on tip of seed-coats & it is to show this that drawing is given; by growth of arched stem with this point on heel holding down lower point, the seed-coats are torn open.

Mark on back 61z

Cucurbita ovifera: germinating seed with heel projecting from base sum of arched hypocotyl radicles & resting on lower apex of — seed coats, by which means these are finally soon ruptured & cast off.

[66]

Megarrhiza Delphinium nudicaule Jan 19 / 80

Dug up the specimen we looked at with an arched leaf appearing at the surface

This leaf has a sinuous petiole and at 11mm below the top of the arch, it comes out of a split in the united cotyledon-petioles

There is a second true leaf 5mm in length which has come out of the crack & is arched but strt

[annotated figure]

[67]

Delphinium

[Figure] HK 2 CL

leaf 1

tip of mid-petiole leaflet bent back by going up tube

old leaves sometimes have tip like this which seem to drop off

There is no plumule