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Darwin Correspondence Project

From Asa Gray   5 September 1862

Cambridge. [Massachusetts]

Sept. 5. 1862

My Dear Darwin

Thanks for yours of Aug. 9.1 Lythrum Hyssopifolia is not in my reach.2 Get it from France, where it is common. I may, perhaps, get you L. lineare & alatum thro. correspondents. Nesæa verticillata I will send you seeds of. Probably a very hopeful plant for your purpose3

Mitchella—you will hardly be able to raise from seed.4 But I mean to send you this autumn patches of it—hoping to get better sorts,—and live roots of Cypripedium.5 Let them rest in the cold till Xmas, & then they will flower in your room very well.

So you have paid for the Orchid-Books sent by Trübner!6 Well, I had given away a part, and shall so arrange for the rest. I hope to get observations & fresh orchids in return.

Rothrock suddenly enlisted from Pennsylvania, & is before the enemy!7

I am so glad to hear of your boy’s recovery.8

Of observations, I have little to say this time. Impatiens sends off pollen tubes out of the anthers of the precociously fertilized blossoms. I could not get specularia. But Torrey says he could not find the pollen-tubes coming out.9

No Lythrum within my reach here.

In Ammannia, I have distinguished 2 species by length of style, dimorphic—no doubt, though the 2 species are good.

Goodyera repens & I believe pubescens also. The column of the flower turns back a little & exposes the stigma in the older flowers.— not the labellum drum. 10

Spiranthes cernua. The difference between the older flowers & those first opened is striking. The latter presents the disc—the former the stigma. But here too, I am very confident the change not in the position of the labellum—but in that of the column!11

You have opened a rich mine indeed among dimorphic & trimorphic? flowers.

Ever— in haste— Yours | most cordially | A. Gray

CD annotations

0.3 My Dear … enemy! 4.1] crossed ink
6.1 Impatiens … specularia. 6.2] double scored ink
8.1 In … good. 8.2] double scored ink
9.1 Goodyera … change 10.3] scored ink; ‘Orchids’ opposite page ink
Top of first page: ‘Dimorphism’ ink; ‘Orchids’ del ink


CD was working on trimorphism in Lythrum salicaria, and had asked Gray if he could obtain specimens of the rare L. hyssopifolia (see letter to Asa Gray, 9 August [1862]).
In his letter to Gray of 9 August [1862], CD commented that he expected Nesaea verticillata (a synonym of Decodon verticillatus, swamp loosestrife), a member of the Lythraceae, to be trimorphic.
CD asked for seed of Mitchella in his letter to Gray of 9 August [1862].
CD had been impressed with Asa Gray’s observations on American species of Cypripedium (see letter to Asa Gray, 1 July [1862]).
See letter to Asa Gray, 9 August [1862] and n. 4. Gray had asked CD to arrange for six copies of Orchids to be sent to him by the London bookseller and publisher Nicholas Trübner (see letter to Nicholas Trübner, 23 June [1862]).
Joseph Trimble Rothrock was Gray’s assistant and student at the Lawrence Scientific School, Harvard University; Gray had sent Rothrock’s observations on Houstonia caerula in his letter to CD of 4 August 1862. Rothrock enlisted in the 131st Pennsylvania Infantry on 1 July 1862 (DAB).
Gray refers to Leonard Darwin, who was recovering from scarlet fever.
Gray refers to his former mentor and botanical collaborator, John Torrey (see letter from Asa Gray, 18–19 August 1862 and n. 5).
Gray included his observations on this point in A. Gray 1862b, p. 427, noting: ‘we suspect that it is the column, rather than the labellum, which changes its position, but we have not been able to demonstrate it’. CD cited Gray’s findings in ‘Fertilization of orchids’, p. 151 (Collected papers 2: 148). Spiranthes cernua is common ladies’ tresses.


Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

DAB: Dictionary of American biography. Under the auspices of the American Council of Learned Societies. 20 vols., index, and 10 supplements. New York: Charles Scribner’s Sons; Simon & Schuster Macmillan. London: Oxford University Press; Humphrey Milford. 1928–95.

‘Fertilization of orchids’: Notes on the fertilization of orchids. By Charles Darwin. Annals and Magazine of Natural History 4th ser. 4 (1869): 141–59. [Collected papers 2: 138–56.]

Orchids: On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. By Charles Darwin. London: John Murray. 1862.


Suggests CD try to get Lythrum hyssopifolia from France.

Dimorphic flowers.

Differences between newly opened and older orchids.

Flowers of Spiranthes and Goodyera.

Letter details

Letter no.
Asa Gray
Charles Robert Darwin
Sent from
Cambridge Mass.
Source of text
DAR 111: 81, DAR 165: 117
Physical description
ALS 3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 3712,” accessed on 25 July 2024,

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