May 27, 1909] 



NA TURE 



technical requirements, are sufficient to guide even 

 a beginner, and this is attained, among other means, 

 by the inclusion of the whole account in a single 

 paragraph, in place of the old plan of subjoining 

 to an often curt diagnosis, sometimes barely intelli- 

 gible without special study of the family or genus, 

 a more or less loosely constructed note, usually in 

 small print, on sundry features of the species, which 

 might or might not, as things fall out, fulfil the end 

 of a detailed description. 



Another commendable feature of the work is pre- 

 sented in the analytical keys that are prefixed to 

 the larger or more difficult genera. There is nothing 

 e£>sier, in a way, for a systematic writer than to 

 make such a key on paper, and the more easily it 

 has been made the more likely is it to be found in 

 practice unworkable, or worse than useless ; but the 

 keys in this instance have been manifestly framed 

 with some regard to the natural groupings of the 

 species, and are clearly the result of personal and 

 accurate examination of the material. As illustra- 

 tions we may mention the synopsis at pp. 98-9 of 

 the Bombay species of Diospyros, of Cordia (p. 199), 

 Strobilanthes (pp. 365-6), and of the often almost 

 hopeless genera of grasses (in the stricter sense). 

 For the last-named very important family — the despair 

 almost of taxonomists — Dr. Cooke has followed rather 

 closely the arrangement made by Dr. Otto Stapf in 

 the " Flora Capensis," which is that most generally 

 now adopted, and, whatever may be thought of this 

 as a comprehensive scheme for this difficult family, 

 it must be admitted that Dr. Cooke's treatment of 

 such genera as Panicum and Eragrostis, to say 

 nought of Andropogon, has been fitted to it in a very 

 workmanlike and skilful manner, without sacrificing 

 detailed observations of the actual structure of the 

 species, that are palpably the fruit of indefatigable 

 work with the lens, by the author. 



A like scrupulous accuracy pervades the nomen- 

 clature throughout the volume, though in some cases 

 whole-hearted disciples of the Vienna Congress will 

 miss sundry emendations that have doubtless been 

 avoided purposely, for reasons analogous to those that 

 have dictated, in the preparation of these Indian and 

 colonial floras, adherence to the " Genera Plan- 

 tarum " of Bentham and Hooker, as against the 

 more recent work of Engler and Prantl. In the case 

 of compendia founded, as the present is expressly, on 

 the " Flora of British India," this is practically unavoid- 

 able, but in the analysis of families, and in some 

 minuter matters. Dr. Cooke has shown, if anything, a 

 shade too much deference to those monumental 

 authorities. Take, for example, the arrangement of 

 the tribes and subtribes in Compositae (pp. 1-6). 

 Assuming that Astereae can be kept up as a tribe 

 apart from Inuleae, and that both should continue, even 

 in a linear arrangement, to stand far apart from 

 Senecionideae through the intercalation of Heliantho- 

 ideae, Helenoideae, and Anthemideae, surely it is time 

 to revise the subtribes of Astereae. No doubt 

 the solitary representative of the genus Erigeron 

 found in Dr. Cooke's area, if it should be 

 kept as an Erigeron at all, conforms to the defini- 

 NO. 2065, VOL. So] 



tion of the subtribe " Heterochromeas " by G. 

 Bentham; but discoveries by the ,'\bb6 Delavay, by 

 Wilson, and others in the Indo-Chinese region have 

 shown that there are true Asters, and perhaps 

 members of the allied genus Erigeron, that have 

 the disk florets of the same bluish tint as the ligules, 

 though of deeper intensity. In the " Genera Plan- 

 tarum " it was admitted that in several genera all 

 the florets are yellow, but now that the converse 

 exception is known to affect the type-genus of the 

 tribe, the division into Heterochromeas and Homo- 

 chroineae seems to call for reconsideration. 



A minor case' suggests itself at pp. 1030-31, where 

 the careful work of Jaubert and Spach on the actual 

 forms of Melanocenchris has been swamped for the 

 sake of resuscitating Koenig's practically barren title 

 for the genus (Gracilea). This, of course, is a debat- 

 able example, but the same can hardly be said for the 

 citation of Linnaeus at p. 479 for the genus Boer- 

 haavia, which Linn^ himself was most careful to 

 attribute to its real author, Vaillant. In restoring 

 B. diffusa, Linn., to the rank of a variety. Sir Joseph 

 Hooker had, in fact, given the clue, because one or 

 other of the two forms put under B. repens in the 

 " Species Plantarum " was the type of Vaillant's genus. 

 Whether either of those be identical with the B. 

 diffusa of Linn6 can be decided only by inspection 

 of the authentic types collected in Abyssinia by Lippi. 



Dr. Cooke's " Flora " was commenced in 1900, and 

 the first part appeared in July, 1901. On May i, 

 1902, the Bombay herbarium at the Poona College 

 of Science was destroyed by fire, and he has since 

 had to depend largely on his own collections and 

 those of Woodrow to supplement the classical 

 material at Kew. He has examined and described 

 2502 indigenous species, and dealt with more than 

 500 introduced or cultivated plants known to the 

 Presidency, distributed among 1029 genera and 148 

 families, embracing types of widely divergent afiini- 

 ties, and belonging to such diverse phytogeographical 

 regions as the Oriental, East African, and Indo- 

 Malayan. It is no mean achievement in itself to 

 have completed such a task successfully. The final 

 part is accompanied by a carefully prepared index to 

 the book as a whole, and this is in two parts, the 

 vernacular names being indexed by themselves, which, 

 for most purposes, is the most convenient arrange- 

 ment. 



THE TEACHING OF PHYSICAL CHEMISTRY. 



(i) The Elements of Physical Chemistry. By Prof. J. 

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(2) OidUues of Physical Chemistry. By Dr. George 

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 Co., n.d.) Price 3^. 6rf. 



(i) 'T'HE fact that the former of the above-mentioned 

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