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Darwin Correspondence Project

To G. H. Darwin   10 [July 1878]1

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.


My dear George

I am so much interested in the Thalia, that I shd. be very glad of sketch of pistil, just beginning to curve & & another sketch of pistil naturally wound up into spire.—2 I know it is a shame to ask you, as you are working on such much more important subjects.—

The specs are in spirits & water & will keep for a few days. It will be impossible for you to do it, unless you can borrow microscope with very weak simple lens. I send diagram of the more interesting specimen, which was almost killed with Prussic acid, so that pistil would move a little from the enfolding petal when I dissected away all the petal except the enfolding one.—3 I cannot yet make out positively what keeps it in place. The 2 transverse nectaries are important; & so is a little white fold at base of lower nectary. The Pistil rises from middle of Ovarium—base of petal of course on one side.— The rectangularly bent summit of pistil, which is seen obliquely in the position shown in diagram, is very complex— If you can, you may afterwards cut it off & draw it from above or any other position.—

On summit there is white knob (in front of concavity in which the pollen is lodged) which I believe is the stigma, with a second stigma in the deep cavity below.—

The second spec. shows pistil & enfolding petal after it had exploded from a touch to tip of nectary with pistil wound into a spire.— Whether you will succeed is a mere chance; but you will fail without microscope

Yours affectly | C. Darwin


The month and year are established by the relationship between this letter and the letter to Francis Darwin, 7 [July 1878].
George often provided drawings for CD’s botanical research (see Movement in plants, p. 8). CD was interested in determining whether the pistil of Thalia dealbata (powdery alligator-flag) was itself irritable or whether its movement was purely mechanical (see letter to Francis Darwin, 7 [July 1878]). For George’s diagram, see the enclosure to the letter from G. H. Darwin, 12 July 1878. CD’s diagram has not been found.
CD’s notes on the application of various acids including prussic (hydrocyanic) acid are in DAR 209.13: 2–11.


Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.


Asks for sketches of [Thalia] pistil, in which he is much interested.

Letter details

Letter no.
Charles Robert Darwin
George Howard Darwin
Sent from
Source of text
DAR 210.1: 69
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11597,” accessed on 22 April 2021,