Ɛpsilon

From Asa Gray   3 February 1880

Herbarium of Harvard University,| Botanic Garden, Cambridge, Mass.

Feb. 3 1880.

My Dear Darwin

Your letter of the 19th ult, made me open my eyes.1 I am just off on a little journey, and have only a moment to say that Mr. Watson, Prof. Goodale, my artist who drew the figures & others can make affidavit to the facts.2 Two or three plants—on one, I think fully 2 inches of the seeming radicle was out of ground3

There are 3 or 4 species. The second lot I sent you was probably different from the first, or of 2 species.4

If your plants were weak, even of the same species, it might account for their not lifting the weight of the seed.

About nomenclature, following the current nomenclature I called the hypocotyledonous internode radicle—properly caulicle.5

Please call all below it root, so as to avoid confusion, “Perennial” I should think so! The root is said to be sometimes of the size of a barrel. Those I have seen in California were from the size of a carrot to that of the biggest ruta-baga.: the tip near the surface of the ground,—but under it, where there was no wash.6

In haste | Ever Yours | Asa Gray

CD annotations

2.1 If your … the seed. 2.2] scored red crayon
Top of letter: ‘In my case petioles geotropic— In Asa Gray apogeotropic!!’7 ink
2
Sereno Watson was the curator of the herbarium at Harvard (ANB); George Lincoln Goodale was professor of botany at Harvard. The figure in Gray’s botanical textbook (A. Gray 1879, p. 21) illustrating the development of a seedling of Megarrhiza californica (a synonym of Marah fabacea, California man-root) did not show which part of the seedling was below ground; no artist is credited for the illustrations in the textbook. In his article on the germination of the genus Megarrhiza (A. Gray 1877, p. 23), Gray had reported that the body of the seed was raised well outside the soil on what seemed to be a well-developed radicle.
3
In Movement in plants, p. 82, in his copy of Gray’s figure of the Megarrhiza seedling, CD added a dotted line to indicate that most of the illustrated seedling was below the ground.
4
CD had first requested seeds of Megarrhiza from Gray in October 1879 (see Correspondence vol. 27, letter to Asa Gray, 24 October 1879); he received some in December (ibid., letter to J. D. Hooker, 19 December [1879]), but later reported that some of a second batch of seeds failed to germinate (letter to Asa Gray, 17 February 1880). For the species of Megarrhiza recognised at this time, see A. Gray 1877; see also Stocking 1955).
5
In the glossary of his textbook, Gray defined the caulicle as the initial stem in an embryo; the radicle of the embryo was defined as the hypocotyledonary and primary internode (A. Gray 1879, pp. 401, 429–30). In Movement in plants, p. 5, CD defined the stem supporting the cotyledons as the hypocotyl; it was distinguished from the radicle only by the presence of root-hairs in the latter.
6
CD had asked whether Megarrhiza californica was an annual or perennial (letter to Asa Gray, 19 January 1880). The rutabaga or swede (Brassica napus var. napobrassica) is a cross between a turnip (B. rapa) and a cabbage (B. oleracea).
7
CD described the petioles of Megarrhiza californica as completely confluent, forming a tube; he noted that as soon as they protruded from the seed, they were strongly geotropic and penetrated the ground unless they met with an obstacle; in that case, the cotyledons were lifted above the ground (Movement in plants, p. 81).

Please cite as “DCP-LETT-12455,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-12455