350 SCIENCE PROGRESS 



bearing of our present knowledge of the Bennettiteae on the problem of the origin 

 ■of Angiosperms, has sufficiently emphasised the fact that the whole question really 

 turns on what our conception of the primitive type of Angiospermous flower may 

 be. It is obvious that if the flowers of Casuarina and the Piperaceae are really 

 primitive, the discovery of the amphisporangiate strobilus of Bennettites has little 

 01 no bearing on this problem. It is only if we can show that such flowers as those 

 of Liriodendron and other members of the Ranales have retained the larger 

 number of archaic features, that the Bennettitean strobilus has any special signifi- 

 cance in this direction. 



The completed Studies, as we now have them, form undoubtedly the best 

 introductory text-book to Fossil Botany in existence from the botanical stand- 

 point, although it makes no pretence of covering the whole ground. It has been 

 rewritten with all the author's well-known charm, clearness and accuracy. The 

 printing is careful, the type excellent, and the wealth of illustrations generous, no 

 less than thirty- six new figures appearing in this volume alone. 



E. A. Newell Arber. 



(Ecology of Plants : an Introduction to the Study of Plant-communities. 



By Eug. Warming, assisted by Martin Vahl. Prepared for publication 

 in English by Percy Groom and Isaac Bayley Balfour. [Pp. xi + 422.J 

 (Oxford : Clarendon Press, 1909. Price Ss. 6d. net.) 



ABOUT ten or twelve years ago, the Delegates of the Oxford Press announced their 

 intention of publishing a translation of Warming's Plantesamfund. The promise 

 has not been fulfilled : and English students have become familiar with Warming's 

 work in the German translation, under the title CEcologische Pflanzengeog?-aphie ', by 

 Knoblauch. In default of the promised translation, there now appears the present 

 volume, which, states Warming in the author's preface, is practically a new work. 

 It has evidently been written in English by Warming ; and to the English manu- 

 script Dr. Groom has, we are informed by Prof. Balfour in a note, "applied with 

 untiring patience his skill in interpretation and in apt expression." 



Although British ecology is, at the present time, in a flourishing condition, its 

 ■early inspirations come from continental botanists. The influence of Flahault, 

 through his pupil Robert Smith, is well known ; and, whilst no British ecologist 

 appears to have ever studied under Warming, his influence on the growth of 

 ecology in these islands has been no less marked. 



At the time of its publication, Warming's earlier work was the only text-book 

 on the subject. " When I wrote it," says Warming, " I had no models to study." 

 It must be stated, however, that every subsequent author has been able to find in 

 Warming's Plantesamfund an excellent model of what a text-book should be. 

 .Simple, clear, and logical, it has had enormous influence. It set out four great 

 types of vegetation ; and based these on the water-content and to some extent on 

 the mineral content of the soil. The four types were Hydrophytes, Xerophytes, 

 Halophytes, and Mesophytes. Later writers have criticised, and some have 

 severely criticised this classification ; and the open-mindedness of Warming is 

 seen in various references to these criticisms. For example, Warming now 

 emphasises the view that "a halophyte is in fact a special form of xerophyte, 

 as Clements repeatedly urges, and Wiesner and Schimper recognised" (p. 134). 

 Whilst Warming, however, has evacuated certain of his earlier positions, he has 

 not dismantled them ; for we read (p. 228) that " there is always a question " with 

 regard to the vegetation on sandy sea-shores " as to whether this formation must 



