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

Extracts from MS of Vol. 4 of Cybele Britannica.²

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.