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Darwin Correspondence Project

From H. C. Watson  14 December [1857]1

Thames Ditton | S.W.

14 Decr

My dear Sir

I will return your list of varieties in British Plts with some notes in course of few days.2 But it is to be feared that I can very imperfectly meet your object.

1. As to the actual commingling:—it is seldom I can say aught of this. Many of the vars. or subspecies I have seen only in gardens & herbaria. And of those which I have myself picked wild,—in divers instances I cannot now recollect whether mingled with the type or not.

2— As to difference of situation:— This is pretty often the case. For instance, there are maritime & alpine forms of many inland & lowland plants. In their appropriate places (shores & hills) they remain so different, as usually to be retained in lists for distinct species. And where the differences are less obvious, or transition forms frequent, they are set down as species & vary.— Corresponding instances occur with plants of relatively dry & wet places. But as the cause of the variety is here usually obvious, it is less frequently deemed a species, & often passed by.

Thus, Polygonum amphibium diag α natans

β terrestreramme are two states of a species, which no botanist would have united into one species, if they had arrived in England from 2 different countries. They are not in your list, just because they are known to be varieties from situation;—the very fact you want to reach thus causing their exclusion.

3. Area. Within our limited Country the area or geographic space of varieties is usually an included & considerably smaller portion of the area of the type species. (On a wider view, there are varieties outside the area of the type species. For instance, there are boreal or arctic forms of temperate species.) Alpine forms with us are usually not included in the area of the type species;—but they overlap somewhat.—

I wish your list had been taken from the 1857 edition of the London Catalogue.3

In answer to your question about the Cybele Britannica,—I quite hope to commence printing Vol. 4 by or before Spring. But the result of so much labour is so often compressed into two or three figures (nos.) that progress is slow.—4

Yours very truly | Hewett C. Watson To | C. Darwin | Esq

CD annotations

crossed pencil
Top of first page: ‘Remarks on Range [over ’&‘] & Stations of varieties.—’ ink; ‘All used’ pencil, circled pencil


Dated by the relationship to the letter from H. C. Watson, 20 December [1857].
CD’s list of varieties extracted from the fourth edition of Hewett Cottrell Watson and John Thomas Irvine Boswell-Syme’s London catalogue of British plants (Watson and Syme eds. 1853) is in DAR 45: 9–15. His calculations relating to the list are in DAR 16.1: 128–33, 173–88. See also letter from H. C. Watson, 20 December [1857].
CD used Watson and Syme eds. 1853 for his Table I (Natural selection, p. 149), but for the ranges of species he used the subsequent edition (Watson and Syme eds. 1857) (Natural selection, p. 168).
Although the printing of the fourth volume of Waton’s Cybele Britannica commenced in 1858, it was not published until 1859 (Watson 1847–59, 4: 3).


Will shortly return CD’s list of varieties of British plants. Discusses the situations in which different varieties of species are often found and the ranges of varieties relative to those of the species.

Letter details

Letter no.
Hewett Cottrell Watson
Charles Robert Darwin
Sent from
Thames Ditton
Source of text
DAR 98: A11–12
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 2183,” accessed on 23 May 2019,

Also published in The Correspondence of Charles Darwin, vol. 6