BOOKS REVIEW K I). 



275 



never shrunk. Chapters II. and III. are upon " the Lesson of the British 

 Flora," and the author deduces the same results: that waterside plants 

 as a rule possess buoyant seeds or fruits. 



He quotes Dr. Schimper in attributing to natural selection the differ- 

 ences between coast and inland plants in their adaptation to floating in 

 the same or allied species ; but the difference in the amount of water 

 seems to be sufficient to account for them. " The same buoyant tissue is 

 present, but much diminished, in the inland plants," which is just what is 

 to be expected as the result of adaptation. 



Chapter XIX. and subsequent ones deal with a variety of interesting 

 subjects, e.g. The Physical Conditions of the Islands, The Age of Ferns, 

 The Era of Endemic and Non- Endemic Genera, Beach and River Drift, 

 Viviparous Mangroves, Seed Dispersal and Geological Time. 



The reader will find much to interest him in this new and standard 

 work on the subject of which it treats. 



" Species and Varieties, their Origin by Mutation." By Prof. Hugo 

 De Vries. Edited by D. T. MacDougal, Assistant Director of the New 

 York Botanic Gardens. 8vo., 847 pp. (Kegan Paul, London.) 21s. net. 



This volume contains twenty- eight lectures delivered at the University 

 of California in 1904, grouped under the following headings : Introductory, 

 Elementary Species, Retrograde Varieties, Eversporting Varieties, Muta- 

 tions and Fluctuations. The meaning of these terms is as follows : De 

 Vries regards " elementary species " as forms wmich suddenly arise with 

 entirely new characters, no one being predominant, so that a species is 

 like a genus, a name for the whole collection of elementary species. 

 Varieties differ from the above in the loss of some character, or rarely in 

 the acquisition of a character already seen in allied species. 



"Fluctuating" is the same as individual variations which are not 

 constant but oscillate about a mean ; while mutations are " sports or 

 single varieties, not rarely denominated spontaneous variations, for 

 which I propose to use the term mutations " (p. 191). 



In dealing with these, numerous matters of great interest are discussed, 

 such as Darwinism and theories of descent, elementary species in nature 

 and under cultivation, stability and atavism, latent characters, crossing 

 and Mendel's law, monstrosities, double adaptations, usually called 

 "amphibious species," the production of double flowers, peloric Linaria, 

 concluding with artificial and natural selection. 



"Experiments with Plants." By W. J. V. Osterhout, Ph.D., Assist- 

 ant Professor of Botany in the University of California. 8vo., 492 pp. 

 (Macmillan, London.) 5s. net. 



This book contains ten chapters dealing with the Awakening 

 and the Establishment of Seeds, the Work of Roots, Leaves, Stems, 

 Fkrwers, and Fruit, How Plants are Influenced by their Surroundings, 

 and Plants which cause Decay, Fermentation and Disease. There are 

 253 illustrations. The plan of the work is a combination of questions 

 with descriptions, the former to be worked out by the pupils approxi- 

 mately ; so that everything is brought under the eyes of the student. 



t 2 



