CURRENT LITERATURE 
BOOK REVIEWS 
Biology of aquatic plants 
The writer of this interesting volume? has rendered a service to botanists in 
summarizing and bringing together the extensive but widely scattered work 
that has been done on aquatic seed plants. Mrs. ARBER’s work, however, is 
far more than a compilation, for every chapter contains interpretive portions, 
and in many of them the summary of the literature is but a scaffolding for 
further records or conclusions. Certain chapters are greatly enriched by the 
author’s own experimental and philosophical conclusions. 
Members of this biological group are of special interest because of their 
double specializations, first as terrestrial plants that have achieved flowers and 
seeds, and secondly because of the more or less marked modification of struc- 
ture and reproductive method as now related to the aquatic environment. 
The volume will be of interest to all botanists, for the subject matter is ably 
grouped around fundamental biological topics, many of them most favorably 
illustrated by aquatic Angiosperms. 
Part I deals with water plants as a whole, and takes up typical life histories, 
starting with a biological classification of hydrophytes in relation to water and 
substratum. The author then proceeds to discuss the vegetative structure of 
typical aquatics, including the marine Angiosperms, which are discussed in the 
concluding chapter of this section. In Part II the anatomy of leaves, stems, 
and roots is considered, together with modifications of the external form of 
these organs. The development of turions, or winter buds, is discussed, and 
the later portion of this section takes up flowers, pollination, fruits, and seed 
dispersal. Part III presents an analysis of the cheebieial ‘oudiitions of the 
water habitat and the application of these to aquatic plants. This section is 
concluded by a chapter on the ecology of hydrophytes, which is conservatively 
handled, a topic which in the hands of some might perhaps have given title to 
the book. Part IV is concerned with philosophical discussions dealing with 
the dispersal and geographic distribution of water plants, their possible origin, 
and their relations to the theory of natural selection. The — chapter 
involves a summary of the author’s work on the phyllode theory 
e volume is attractively printed and illustrated by 171 text figures, 
Sana of them original. The bibliography occupies seventy-two pages, 
and is made fully available by means of an appended index to the genera and 
ARBER, AGNES, Water plants, a study of aquatic Angiosperms. 8vo. pp. 
xvi+436. he. 171. Cambridge University Press, England. 1920. 
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