Botany. 167 



5. A Pocket Handbook of Minerals, designed for use in 

 the field or class-room, ivith little reference to Chemical Tests ; 

 by G. Montague Butler. Pp. ix, 298 with 89 figures and 5 

 tables. New York, 1908 (J. Wiley '& Sons). — Mineralogists and 

 others who feel the need of a small volume suitable for the 

 pocket, giving the important characters of the prominent mineral 

 species, will find this work suited to their needs. It is printed 

 in particularly clear, open form, with the emphasis upon essential 

 characters and the omission of unnecessary detail; there are 

 numerous illustrations. A novel feature is the series of tables at 

 the end presenting the characters of the species in condensed 

 form. 



II. Botany. 



1. The Origin of a Land Flora; a Theory based upon the 

 Facts of Alternation ; by F. O. Bower, Regius Professor of 

 Botany in the University of Glasgow. Pp. xi + 727, with frontis- 

 piece and 361 text-figures. London, 1908 (Macmillan & Co.). — 

 Professor Bower has long been recognized as one of the ablest 

 authorities on the morphology of the Pteridophytes, a group of 

 plants to which the present work is largely devoted. He clearly 

 shows that representatives of this group were the first plants to 

 solve successfully the problems of terrestrial life, and that the 

 Phanerogams, or seed-bearing plants, which are now in the 

 ascendant, were derived from the Pteridophytes by further special- 

 ization. The evidence for these opinions is drawn almost entirely 

 from the sporophyte, or asexual generation, the lines of gameto- 

 phytic development in land plants reaching their culmination in 

 certain divisions of the Bryopl^tes. The great gap which exists 

 between the bryophytic sporophyte with its continuous spore- 

 cavity and lack of lateral organs and the pteridophytic sporo- 

 phyte with its distinct sporang'ia and well developed leaves is 

 still unfilled, but three main factors of advance are indicated, 

 namely : sterilization of originally fertile cells ; segregation of 

 sporogenous tissue into distinct masses ; formation of roots and 

 of appendicular organs, such as leaves, on the axis or stem. The 

 fact is also emphasized that the primary function of the sporo- 

 phyte is, after all, the production of spores, so that, in the evolu- 

 tion of the Pteridophytes, the sporophyll was probably the first 

 type of leaf to appear, the true foliage leaf arising from the 

 sporophyll by further sterilization. On the basis of these views 

 the author advances the idea that the sporophyte in the original 

 Pteridophytes consisted of an axis attached to the soil by a root- 

 system and bearing a cluster of small sporophylls, each with a 

 single sporangium. The closest approach to this condition is 

 apparently to be seen in such a plant as Lycopodium Selago, 

 where the sporophylls are indefinite in position and essentially like 

 the small foliage leaves in appearance and structure. The large 

 and frequently compound leaves which are characteristic of the 

 Filices and Ophioglossales have apparently been derived from 

 small and simple leaves by longer continuance of growth and 

 increase in complexity. Professor Bower designates the theory 



