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Darwin Correspondence Project

From H. C. Watson   20 December [1857]1

Thames Ditton

20 Decr

My dear Sir

I have taken up your list of British plts with subspecies or varieties several times during the week, & still with the same idea arising;—namely, that I am not prepared to go seriatim through it in the manner, & with the brevity, you desired.—2 I do not think any botanist can. And thus, I fear, the only result of my beginning to write notes on your list, is, that the list is defaced & spoilt for any other use.

In writing the final volume of my Cybele Britannica, I find myself unable to carry out the ideas or inquiries originally intended.3 And why?— Mainly, because the limits of species are so uncertain in nature,—so dissimilar in books. Add to this, the extreme inequality in the Structural value of groups designated by the same abstract term (ex. gr. Orders). The result is, I can only group & compare details,—not condense them into real generalisations.

This leads me to devote many pages to my own notions about species & classifications,—rather irrelevant in a book on local botany;—& perhaps somewhat limping over that same ground which will be better trod by yourself.4 I cannot find the proof of species being definite & immutable, whatever they may seem to be at any one time & spot.—

Sincerely | Hewett Cl. Watson Charles Darwin | Esq


Dated by the relationship to the letter from H. C. Watson, 14 December [1857].
See letter from H. C. Watson, 14 December [1857]. The list, with Watson’s markings, is in DAR 45: 9–15.
Watson was preparing the fourth volume of Cybele Britannica (Watson 1847–59).
Watson paid considerable attention to the problem of defining species (Watson 1847–59, 4: 27–44).


Watson, Hewett Cottrell. 1847–59. Cybele Britannica; or British plants and their geographical relations. 4 vols. London: Longman.


Finds he cannot annotate CD’s list of subspecies and varieties as wanted. Mentions again his difficulties with "species"; he "cannot find the proof of species being definite and immutable whatever they may seem to be at any one time and spot".

Letter details

Letter no.
Hewett Cottrell Watson
Charles Robert Darwin
Sent from
Thames Ditton
Source of text
DAR 98: A13–14
Physical description
ALS 3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 2190,” accessed on 12 September 2023,

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