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Darwin Correspondence Project

From H. C. Watson   [after 23 March 1858]1

Extracts from MS of Vol. 4 of Cybele Britannica.2[DOUBLE UNDERLINED]

Perhaps the tabular & numerical form may best illustrate the wide diversities of view as to species, prevalent among botanists who have published Floras of the British Islands within the last half century or a little more. The number of species into which the several Authors have divided some of the larger genera, is indicated opposite their names in the subjoined list; changes in the genus under which any given species was placed, being allowed for in reckoning the number of species. The same sort of allowance, towards reduction of numerical discrepancies, could not be made so exactly in the case of added species; because it is occasionally very difficult to decide whether an Author was unacquainted with the “species” since described as novelties by his successors, or whether he had regarded them simply as states or varieties of those which were described by himself. I use such editions as happen to be at hand, identifying them by their dates.3

Withering Hudson Smith Withering Smith Gray Smith Hooker Lindley Hooker Babington Arnott Babington4 1796 1798 1800 1812 1818 1821 1828 1835 1835 1842 1843 1850 1856 Rubus. 6 5 7 7 8 8 14 13 21 14 24 5 41 Salix 22 18 45 48 56 56 64 71 29 70 57 37 32 Hieracium. 10 7 10 13 16 16 16 18 17 13 19 18 33 Potamogeton 11 12 10 13 12 14 13 15 12 17 19 18 21 Saxifraga. 11 9 14 13 20 25 25 21 24 16 20 16 20 Poa. 14 15 16 17 20 15 14 15 15 20 16 21

Thus, whether we compare together different Authors publishing at nearly the same dates, or the same Author publishing at different dates, much discrepancy appears in their ideas of species. But a separate comparison, or rather contrast, between the varying views of the same Author at short intervals, may even more convincingly prove how uncertain still are the practical ideas about species, as put forth by technical botanists whose business it should be to know species, but who too often only describe them … … … … .

Four successive editions of Babington’s Manual of British Botany, to appearance each one carefully revised, have been published in about a dozen years. The Author of the Manual may be said to know the special botany of the British Islands far more completely & critically than either the first Author or recent Editor (Dr Arnott, editions 6 and 7) of the British Flora5 . I therefore take the four successive editions of the Manual, dated in 1843, 1847, 1851, 1856; and from these I select a score of the genera or sub-generic sections, which are differently divided into species in the several editions. (See the table on the opposite page.)

Such lists as these ought to convince any reasoning man, who may hitherto have imagined Botanic Species to be things fixed and certain in nature, that nevertheless, down to the present time, they are far indeed from being fixed and certain in books. Where then is the proof of their certainty & fixedness in nature? If in existence anywhere, in regard to the plants of England, it ought to be found in the books of a diligent Botanist, who has devoted his attention during many years specially to the plants of this one country, comparatively of small area; who has travelled much over that area, as a practical investigator; and who has well studied the descriptive works relating to the same species of plants in adjacent countries. And yet the books of this Botanist, so far from furnishing proof of fixedness, evidence great uncertainty and variability.

Number of Species under 20 genera, by Babington’s Manual, 4 editions. Rubus Salix Hieracium Galium Atriplex Epilobium Batrachium Arctium Ulmus Filago Cerastium Lastrea Quercus Thlaspi Urtica Sparganium Barbarea Polystichum Pyrethrum Glyceria 1843 24 57 19 15 10 10 4 2 7 3 9 6 3 3 4 3 4 2 3 2 1847 36 58 21 15 11 10 5 2 7 3 9 8 3 3 4 3 3 3 3 3 1851 43 33 27 14 9 11 7 2 2 5 8 8 1 4 3 4 3 3 3 3 1856 41 31 33 17 9 12 12 5 2 5 8 8 1 4 3 4 3 3 2 3

N.B. The genera are so placed in this list as to bring into view the fact, that the changes are not in one direction only, but in the two contrary directions of in- crease and decrease of numbers; and further, that the two kinds of change occur both in large and in small genera.

CD annotations

Top of first page: ‘Ask permission to quote’6 pencil
Bottom of last page: ‘Nothing can show more forcibly that species are not definite like sulphuric or nitric acid’7 pencil


Dated on the assumption that Watson’s memorandum, consisting of extracts from the manuscript of volume four of Watson 1847–59, was sent to CD to clarify Watson’s statements in the preceding letter concerning the discrepancies between different botanists’ classifications of the species and varieties in large genera. Since the manuscript was sent to the printer early in 1858 (Watson 1849–59, 4:3), it is likely that the memorandum was sent before Watson had received proof-sheets (see preceding letter).
The extracts, with some minor differences, are taken from Watson’s discussion of the ‘Uncertainty of species’ in Watson 1847–59, 4: 39–43. CD had asked Watson to send him proof-sheets of the volume (see preceding letter). In the event, it was not published until 1859.
CD had included a similar table, taken from Watson 1845, in chapter 4 of his species book (Natural selection, p. 113). CD had completed this chapter in January 1857 (see Correspondence vol. 6, Appendix II).
The works cited include most of the standard books of English botany: Withering 1796 and 1812; W. Hudson 1798; J. E. Smith 1800, 1818, and 1828; S. F. Gray 1821; Lindley 1835; and Babington 1843 and 1856. The references to ‘Hooker 1835’ and ‘Hooker 1842’ are presumably to the third and fifth editions of William Jackson Hooker’s The British flora (London, 1830). The sixth (1850), seventh (1855), and subsequent editions of this work were edited by George Arnott Walker Arnott.
By ‘the first author’, Watson apparently refers to W. J. Hooker.
CD did not cite this information in Origin.
CD alludes to James Dwight Dana’s analogy between the fixity of species and that of chemical substances. Dana had presented this argument for the immutability of species in Dana 1857, which CD read in December 1857 (see Correspondence vol. 6, letter to J. D. Hooker, 25 December [1857]).


Extracts from MS of vol. 4 of HCW’s Cybele Britannica [1847–59] showing the diversity of views on species among botanists.

Letter details

Letter no.
Hewett Cottrell Watson
Charles Robert Darwin
Sent from
Source of text
DAR 45: 16–17
Physical description
Amem 3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 1808,” accessed on 18 June 2018,

Also published in The Correspondence of Charles Darwin, vol. 7