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Darwin Correspondence Project

To Asa Gray   28 July [1862]1

Down Bromley Kent

July 28th

My dear Gray.—

I hardly know what to thank for first. Your stamps gave infinite satisfaction. I took him first one lot & then an hour afterwards another lot.2 He actually raised himself on one elbow to look at them. It was the first animation he showed. He said only “You must thank Prof. Gray awfully”.— In evening after long silence, there came out the oracluar sentence “He is awfully kind”. And indeed you are; overworked as you are, to take so much trouble for our poor dear little man.—

And now I must begin the “awfullys” on my own account: what a capital notice you have published on the orchids!3 it could not have been better; but I fear that you overrate it. I am very sure that I had not the least idea that you or anyone would approve of it so much.— I return your last note4 for chance of your publishing any notice on subject; but after all perhaps you may not think it worth while; yet in my judgment several of your facts, especially P. hyperborea are much too good to be merged in a Review.5 But I have always noticed that you are prodigal in originality in your Reviews.— I wish with all my heart I could understand use of the common vibratile labellum in foreign orchids;6 insects would have to watched at work.—

You speak of two Pogonias always growing together;7 see my account of Aropera, a male orchid.8 Cannot you get a pupil to watch Calopogon? I shd. be very much surprised if insect suck stigma: the speculation crossed my mind & was rejected from want of any analogous case.9 I received two copies of your Review; so I sent one to Hooker,10 as if you have not sent it, he would surely like to see your excellent remarks.— You exactly express my conclusion about Greenland. Hooker, I think, underrates occasional means of transport.11 Till I proved the contrary, he used to maintain vehemently without a fact that the sea would kill all seeds.12 I have not had time yet to look at Mitchellia.13 Cannot you persuade your pupil to protect under fine net & experiment on some plants.—14 Perhaps Houstonia is visited by moths:15 I have reason to suspect that many Galiaceæ are so visited.

I was looking at Lythrum salicaria this morning; it is beautifully dimorphic like Primula, but with addition in both forms (I believe there is a third form) of six short stamens: it will be curious to make out use of them.16

But I must hold hard, otherwise I shall spend my life over dimorphism: what I said about pollens & stigmas of Linum grandiflorum, knowing each other is confirmed by further experiment.17

I have written to Trübner about the copies of Orchid Book.18

Farewell. This is a dull letter & is sent merely to give you my most cordial thanks.— Adios | C. Darwin


The year is established by the references to Leonard Darwin’s illness and to Gray’s review of Orchids (A. Gray 1862a).
Gray had evidently sent a selection of American postage stamps for Leonard Darwin, who was recovering from scarlet fever, with the letter from Asa Gray, 15 July [1862] (see also CD’s annotations to that letter).
Gray’s review of Orchids (A. Gray 1862a) appeared in the July number of the American Journal of Science and Arts; Gray had sent CD a copy of the review (see letter from Asa Gray, 15 July [1862] and n. 16).
CD probably refers to the main body of the letter from Asa Gray, 15 July [1862], which has not been found.
In the letter to Asa Gray, 23[–4] July [1862], CD tried to persuade Gray to publish a separate account of his observations on American species of orchids, rather than merely adding them to his review of Orchids, and sent back all Gray’s notes to enable him to do so. Gray detailed some of his observations, including those on Platanthera hyperborea in the follow-up article to his review of Orchids (A. Gray 1862b); he also gave an account of P. hyperborea in A. Gray 1862c, pp. 259–60. See also letter to Asa Gray, 23[–4] July [1862] and nn. 23–5.
In Orchids, p. 171, CD conjectured that the extreme flexibility and liability to movement of the labellum in some orchids might be designed to attract insects ‘in the same manner as the bright colours and strong odours of many other Orchids apparently serve to attract insects’ (Orchids, p. 171).
CD discussed Gray’s observations on Pogonia in the letter to Asa Gray, 14 July [1862]. From CD’s annotation to the letter from Asa Gray, 15 July [1862], it appears that Gray sent CD further notes on the subject with that letter; these notes have not been found.
CD misspelled Acropera; in Orchids, pp. 206–10, CD noted that, ‘although no instance of the separation of the sexes was known in Orchids’, he had become convinced that the specimens of Acropera luteola he had examined were from a male plant.
Gray’s notes on this species have not been found, but see the letter from Asa Gray, 2–3 July [1862], in which Gray reported his intention of looking at Calopogon pulchellus.
Joseph Dalton Hooker.
The reference is to Gray’s review of Hooker’s paper on the distribution of Arctic plants (J. D. Hooker 1861a), which followed Gray’s review of Orchids (A. Gray 1862a) in the July issue of the American Journal of Science and Arts. In his paper, Hooker sought to explain the general paucity of the Greenland flora on the hypothesis that ‘the polar region was once occupied by the Scandinavian flora’, and that the cold of the glacial epoch drove the vegetation southwards, causing the temperate flora of southern Greenland to be ‘driven into the sea’. Following ‘the return of the heat’, Hooker argued, Greenland would have been repopulated by the migration of Arctic species surviving in the south of the peninsula (J. D. Hooker 1862a, p. 254). On reading Hooker’s paper, CD concluded that ‘during the coldest part of Glacial period, Greenland must have been quite depopulated’, suggesting that it must then have been repopulated by ‘accidental means of transport by ice & currents’ (see letter to J. D. Hooker, 25 February [1862]; see also letter from J. D. Hooker, 3 March 1862, and letter to J. D. Hooker, 7 March [1862]). In his review (A. Gray 1862d, p. 145), Gray reported Hooker’s hypothesis, but stated: Considering the present frigid climate of Greenland, … its moderate summer and low autumnal temperature, we should rather have supposed the complete extermination of the Greenland ante-glacial flora; and have referred the Scandinavian character of the existing flora … directly to subsequent immigration from the eastern continent. See also letter to J. D. Hooker, 4 November [1862].
Starting in March 1855, partly prompted by Hooker’s scepticism on the subject, CD had carried out a series of experiments to ascertain the fertility of seeds after immersion in salt water (see Correspondence vol. 5, letter to J. D. Hooker, 7 April [1855]).
Gray sent CD a specimen of Mitchella repens with the letter from Asa Gray, 15 July [1862].
CD refers to one of Gray’s students, Joseph Trimble Rothrock (see letter from Asa Gray, 15 July [1862]).
CD recorded the first of a series of observations on Lythrum salicaria on 29 July 1862 (DAR 27.2 (ser. 2): 1). See also letter to Asa Gray, 1 July [1862], and letter to W. E. Darwin, 9 July [1862].
Gray had asked CD to arrange for six copies of Orchids to be sent to him by the London publisher and bookseller Nicholas Trübner (see letter to Nicholas Trübner, 23 June [1862], and letter to Asa Gray, 1 July [1862]).


AG’s "capital" review of Orchids [Am. J. Sci. 2d ser. 34 (1862): 138–44].

Thinks there are three forms of Lythrum salicaria.

Discusses transport of seeds by sea.

Letter details

Letter no.
Charles Robert Darwin
Asa Gray
Sent from
Source of text
Gray Herbarium of Harvard University (75)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3667,” accessed on 26 April 2019,

Also published in The Correspondence of Charles Darwin, vol. 10