99 



of regarding the scale as a carpel rather than with Celakovsky, as 

 an outer integument. 



The remaining four chapters of the book are a comparative 

 summary of those preceding, with two devoted respectively to 

 fossil gymnosperms and geographical distribution. The fossil 

 forms are treated practically from the standpoint of Scott and 

 there are new illustrations of Cycadeoidea from the preparations 

 of Wieland, of Yale. One looks perhaps for a rather more 

 thorough treatment of the intermediate group of Cycadofilices 

 from which, according to the authors, the cycads are derived 

 through the Bennettitales, while the Ginkgoales and Coniferales 

 originate through the Cordaitales. This phylogeny looks to the 

 Filicales as the ancestral group of the Gymnosperms because of 

 the close similarity of the Cycads and Cycadofilices. 



The book serves as a very convenient and up to date summary 

 of the literature of the subject; a separate bibliography is given 

 for the five more important chapters and a complete bibliography 

 at the end of the book. The references from the text are made, 

 however, by numbers corresponding to the chapter bibliography, 

 which is not as convenient for the reader as footnotes ; and the 

 chronological arrangement of even the shorter bibliographies 

 seems unnecessary. The half-tone illustrations are not always 

 as satisfactory as the older line work especially for anatomical 

 reproductions (see Fig. 47), or for such morphological details as 

 the seedling leaf forms (Fig. 42), of which the arrangement as a 

 whole is excellent. The book undoubtedly provides a useful and 

 concise review of the present knowledge of Gymnosperms. — 



Louise B. Dunn. 

 Practical Text-Book of Plant Physiology. By D. T. Macdougal, 



Ph.D. Longmans, Green & Co., 1901. 



In this text-book the author departs somewhat from the usual 

 arrangement of the subject found in the majority of plant phys- 

 iologies. In the opening chapter on the " Nature and Relations 

 of an Organism" are found excellently clear and concise defini- 

 tions of such phenomena as rigor, irritability, tonicity, etc., 

 which must be of great service to the student in forming a definite 

 conception of these underlying and often not properly understood 

 principles of plant physiology. Following this chapter are sev- 

 eral on the relation of plants to various external agents. In the 



