670 SCIENCE PROGRESS 



The third section treats of the physiological relations of water plants, 

 and includes a chapter of eight pages on their ecology. This latter is indeed 

 the least satisfactory in the whole work. We cannot but deprecate the 

 suggestion that research in the exploitation of any field of knowledge is the 

 exclusive prerogative of any investigators having one particular view-point. 

 That brcinch of knowledge is greatest which is most truly the servant of 

 others, and the function of each is to supply inspiration to add to the sura 

 of hurnan learning. When, therefore, Mrs. Arber writes that the contributions 

 of ecology to the study of aquatics have not been of first-rate importance, 

 one cannot but note the large number of references in the less strictly 

 ecological matter, to work such as that of Gluck, which had its inspiration in 

 the ecological view-point. We note, too, no mention of Pearsall's important 

 contribution to the role of sedimentation in determining the distribution of 

 aquatics, though the paper itself is quoted in another minor connection. 



In treating of the distribution of aquatics in this country, we are surprised 

 to find no mention of the influence of our elaborate canal system, which 

 formed an unbroken connection between the waterways of the north and 

 those of the extreme south. Also, in considering the effect of buoyancy and 

 its absence, the transporting action of currents during periods of spate must 

 surely be of importance even to seeds of high specific gravity. 



Mrs. Arber repudiates the view that aquatics are the remnants of a 

 decadent and defeated race retreating before the pressure of competition ; 

 rather are they the pioneers suited by their constitution to this particular 



habitat. 



Emphasis is laid on the important part which the Helobiese play in 

 giving an apparently prevalent aquatic habit to the monocotyledons as a 

 whole. The primitive character of this cohort and its characteristically 

 swollen hypocotyl are held to be the determinants of its marked hydro- 



phytism. 



In summarising the bearing of aquatics on evolutionary problems the 

 inheritance of acquired characters is held to be " an almost inevitable article 

 of belief if it is understood in a broad and general sensed 



There is appended an extensive bibliography in which a novel feature is 

 the notes indicative of the chief contents of the papers cited. 



Botanists and naturalists generally should feel indebted to the authoress 

 for having brought together a large mass of scattered information, compiled 

 in a manner which renders the dullest subjects interesting. 



E. J. Salisbury. 



British Plants. By J. F. Bevis, M.A., B.Sc, and H. J. Jefferey, A.R.C.S., 

 F.L.S. 2nd Edition. [Pp. xii -f 346, with 115 figures.] (London: 

 Methuen & Co., 1920. Price 75. 6d. net.) 



As indicated by the sub-title, the aim of the authors has been to treat of 

 British plants from the standpoint of their ecology and biology. Beginning 

 with a general treatment of the factors of the environment, occupying about 

 one-third of the text, the authors pass on to consider the morphology, 

 physiology, and biology of plants in general, thus leading up to the final 

 chapters, in which the plant communities of the British Isles are briefly dealt 

 with. 



The chief modification of the original edition is the addition of about 

 twelve pages of appendix devoted to Weismann's law of heredity, the Mendelian 

 theory, botanical provinces, and a short bibliography. The chapters on 

 ecological matters could with advantage have been drastically revised. 

 Most field botanists will learn with surprise that Iris fcetidissima is commonly 

 found on shifting dunes, whilst the inclusion of Ulex europceus or Teucrium 



