Ɛpsilon

From A. S. Wilson   14 April 1881

North Kinmundy, | Summerhill, | by Aberdeen.

14 April 1881.

Dr. Charles Darwin. | Down | Beckenham | Kent.

My Dear Sir,

I now take the liberty of sending you a cutting from the Gardeners’ Chronicle, being what I dare say will be my last report regarding Kubanka and Saxonka wheat.1 You may see that I have not found any alterations taking place, except such as came about from greater or less supply of food; although at the same time I confess it is not so very easy to determine what is an alteration. Last year, for example, I had stools of barley carrying up to 130 ears from one seed; and if such a plant is compared with another stool carrying only 1 stunted ear, has anything supervened in the way of specific change?2 I suspect that we must look rather to the insidious accumulations of long cosmical periods than to mere cultivation, for alteration of forms—

There is an undecided point incidentally referred to in your last Book to which I have recently been giving some attention, viz. what is the cotyledon of a grass embryo? I have come to the conclusion that the scutellum and not the sheath of the plumule ⁠⟨⁠i⁠⟩⁠s the cotyledon.3 Richard and others say that the scutellum does not grow in germination: I have many mounted specimens showing that the scutellum of the Oat grows in germination to three times the length ungerminated,—that it has a vascular midrib, and frequently acquires a greenish tint.4 The secondary buds which succeed the plumule have also sheaths, very nearly the same as the sheath of the plumule or first bud. I notice that Mr. Henslow gave you an abstract of views held on this subject (The Movement of Plants p. 62) I might perhaps venture to ask him for a copy of it.5

With my very warmest thanks for your kindness in sending me the Russian wheats, | I am | yours very sincerely | A Stephen Wilson.

1
Wilson’s report appeared in Gardeners’ Chronicle, 2 April 1881 (A. S. Wilson 1881). In 1878, CD had asked Wilson to test the claim that Kubanka (a prized variety of Russian wheat) degenerated into another variety, Saxonka, when planted in poorer soil (see Correspondence vol. 26, letter to A. S. Wilson, 24 April 1878). Wilson had published two earlier articles based on his continuing investigation (A. S. Wilson 1879; A. S. Wilson 1880), in which he found that the apparent transformation was merely an artefact of the different productivity of the two varieties.
2
In the context of agriculture, a stool is the complement of stalks produced by one seed of a grain such as wheat, barley, or oats. The number of heads per stool as well as their quality are determined by factors such as depth and distance of planting. By ‘specific change’, Wilson refers to a change in species. CD had discussed the role of the direct action of external conditions in developing new species in Variation 2: 271–92.
3
See Movement in plants, p. 5, for CD’s discussion of terminology; he referred to cotyledons as ‘the organs which represent the first leaves’ (see also n. 5, below). The scutellum is a tissue within the embryo that absorbs the stored food from the endosperm; it was generally regarded as the cotyledon of grasses by the earliest writers on the subject. By this time, however, many botanists thought that the sheath (pileole or coleoptile) of the plumule, or first shoot, was the cotyledon.
4
Louis Claude Richard had expressed this view in Richard 1811, p. 455. The vascular midrib is the central vein of the leaf, characterised by vascular bundles consisting of xylem and phloem. Oat is Avena sativa.
5
CD referred to George Henslow’s abstract of the views of botanists on the nature of cotyledons of grasses in his discussion of circumnutation of the cotyledon of Phalaris canariensis (canary grass; see Movement in plants, p. 62; see also Correspondence vol. 26, letter from George Henslow, [c. 20 February 1878]).

Please cite as “DCP-LETT-13116,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-13116