From H. C. Watson   17 August 1855

Thames Ditton

17 Augt. 1855

My dear Sir

I send the Catalogue of plants by this post, marked in some degree according to your want.1 Perhaps I have marked too many as resembling pairs, by including some species that are always known when once understood. For instance, Chrysosplenium oppositifolium & alternifolium, tho very like, can always be known by the one character implied in the specific names. So again with Drosera intermedia & anglica, plants having a close general similarity, & the names of which have been often misapplied in printed books & on labels with specimens; while the species are always distinguishable by so trifling a character as that of a straight or curved-at-base flower stalk diagram (combined with some other less obvious characters, to make them species).— Not knowing your special object, I cannot, of course, select to suit; & may include what do not apply.

On the other hand, many which I do not mark as close species, simply because entered in the Catalogue as Species & Vary., other botanists would consider to be the close species, while those marked would by them be deemed not close enough to mark, as in the two instances given.

In answer to your query, I do not recollect any stray paper published by myself elsewhere than in Phytologist & London Journal of Botany that would be likely to have interest for you. The enclosed list of papers &c. printed before 1847, (& which was subjoined to Testimonials sent in on my behalf when a Candidate for a Chair of Botany)2 may be received as a general answer.

Lastly, Allow me to say that if I can be of any use to you in small matters, do not hesitate to point out how. From you I shall receive any such application as a Compliment;—altho’ phrenologically speaking, I am not much given to ‘venerate’ others.—3

[Truely] Sincerely Yours | Hewett Cl. Watson To | C. Darwin | Esq

CD annotations

crossed pencil
Top of first page: ‘What [2 words illeg]. your lists of Papers’ pencil, del pencil; ‘(2)’ pencil
1
H. C. Watson and Syme 1853. See letter from H. C. Watson, 13 August 1855, n. 1. CD’s calculations on the close species marked by Watson are in DAR 15.2: 8–10. Other calculations on the same subject, but dated October and November 1855, are in DAR 15.2: 11–14. See also Natural selection, pp. 112–13, where CD reported that Watson had informed him that in marking the species in the London catalogue, he had found ‘that there are about 1800 names which have been considered by some Botanists as Species, but that out of this number, about 450 are considered by other Botanists as mere varieties’. Of the 71 forms that he marked as true species that are also closely related to other species, 57 occur in genera that have 5 species or more and only 14 in genera having 4, 3, or 2 species (Natural selection, p. 148).
2
In 1846, Watson had been an unsuccessful candidate for a chair of botany at the newly established Queen’s College in Ireland (Queen’s University, Belfast).
3
Watson was an advocate of phrenology and had earlier edited the Phrenological Journal.

Please cite as “DCP-LETT-1743,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-1743