To W. T. Thiselton-Dyer   19 and 21 February [1878]1

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

Feb. 19th

My dear Dyer

One line to thank you much for seeds2 & to say that I heard from Saporta this morning. He is particularly obliged to Sir J Hooker & all at Kew, & admits that the fossil is more probably allied to Ceratopteris than to any Angiosperm— He remarks that this Fern is an anomalous form.—3

I do not know whether Hooker (whom I asked the meaning of the sort of joint on the arched plumule of the Onion) would care to hear, but I find that this joint-like structure first appears as a white prominence, which appears to me an adaptation to break through the crust, of earth. Long after the doubled or arched plumule or cotyledon (whichever it ought to be called) has risen some way above the surface of the earth the tip of the plumule lies coiled within the buried seed-coats, evidently absorbing the white abluminous(?) matter still abounding within the seed.4

Ever yours sincerely | Ch. Darwin

P.S | The peduncle of Cyclamen Persica bearing large pod, whilst bowing down to the ground, nutates in all directions. but chiefly earth-wards5

P.S. Feb. 21st

I beg pardon for my stupidity in having put wrong note in envelope.—6 Pray thank Sir Joseph for having sent me G. Henslow on cotyledons of Grasses.— I will keep it, if I do not hear to contrary.—7 If you see Mr Henslow pray give him my thanks, so I suppose he took such enormous labour for Hooker’s sake.

1
The year is established by the relationship between this letter and the letter from Gaston de Saporta, 16 February 1878.
2
CD had asked for seeds of Trifolium resupinatum (Persian clover) in his letter to Thiselton-Dyer of 16 February [1878].
3
See letter from Gaston de Saporta, 16 February 1878; Thiselton-Dyer had sent Joseph Dalton Hooker’s identification of Saporta’s tracing of a Permian leaf in his letter of [before 3 February 1878]. Ceratopteris is a genus of aquatic, homosporous ferns.
4
CD reported these observations on the common onion (Allium cepa) in Movement in plants, pp. 59–60. CD was unsure what constituted the cotyledon in a monocotyledon and whether the part should be referred to as the plumule or the cotyledon; for a discussion, see the letter from J. D. Hooker, [c. 20 February 1878].
5
CD discussed the apheliotropic (growing away from sunlight) movement of the peduncle, or flower stem, of Cyclamen persicum (florist’s cyclamen) in Movement in plants, pp. 433–4.
6
CD accidentally transposed this letter with his letter to D. F. Nevill of 19 and 21 February [1878].
7
Joseph Dalton Hooker evidently asked George Henslow to provide CD with an account of the different views of embryonic organs in grasses; see memorandum from George Henslow, [c. 20 February 1878].

Manuscript Alterations and Comments

1.4 Fern] above del ‘form’
2.5 some way] above del ‘far’
4.1 bearing] above del ‘with’
4.2 to] interl

Please cite as “DCP-LETT-11367,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11367