MORPHOLOGY OF SPEKMATOPHYTES 247 



should welcome a more emphatic separation than is expressed by 

 the view which regards these and the Angiosperms as merely sub- 

 divisions of one of the great divisions of the plant -world. Kobert 

 Brown got as far as that nearly a century ago when he recognized 

 the importance of the difference between an ovule on an open 

 carpel and ovules enclosed within an ovary chamber. But from 

 Hofmeister onwards the tendency of research has been to widen the 

 gulf between the two subdivisions of seed-plants, and to indicate 

 that in the Gymuosperms we have a group, perhaps more than one 

 group, which should rank as a planD-division of equal value to 

 Pteridophyta, holding a position between the fern-plants and the 

 flowering-plauts proper, Messrs. Coulter and Chamberlain might 

 well have seized the opportunity afforded by the publication of a 

 book which recapitulates the results of recent work, and more than 

 auy other emphasizes this position, to recognize that position by a 

 distinctive group name. Part II. of a woriv on the same lines is at 

 present an impossibility. There is much, very much more to be 

 done on the gametophyte stage of the life-hibtory of the Angio- 

 sperms before a volume companion to the one before us can be 

 written. 



As regards the book under review, it is an excellent and authori- 

 tative summary of the general morphology of the Gymnosperms. 

 These are considered as including four series — Cycadales, Ginkgoales, 

 ConiJ'erales, and Gnetales. The second comprises the monoiypic 

 genus Ginkgo, the characters of which, as striking and peculiar as its 

 name, justify its separation from the Conifers as a ditiiinct group. 

 Anatomical details are referred to only where they bear directly upon 

 the general character of the groups ; tiie work does not profebS to 

 be a text-book of anatomy. Cytoiogical details in the gametophyte 

 stage are, on the other hand, very fully described. Nor is the 

 treatment, except for broad distinctions, a systematic one. Genera 

 in each series are referred to as illustrating points in morphology, 

 but the subdivision of the series is barely touched upon. 



Briefly we have here a book which gives just what a student has 

 hitherto been unable to get in a single volume — an intellectual 

 gymnospermous repast almost as perfect, from the points of view 

 selected, as was possible at the time of publication, and set forth as 

 regards typography and illustrations m quite the best neo-American 

 style. Many of the figures are new, occasionally embodying the 

 result of researches hicnerto unpubhshed, as, for instance, in the 

 case of some of those describing the cytology of the gametophyte 

 in the Conifers. 



The authors draw attention to an unusual limitation which they 

 adopt of the two stages in the hfe-history of the plant. They regard 

 the history of the sporophyte as closed with the appearance of the 

 spore motuer-cell rather than with that of the spore. " Tnis has 

 seemed to us to be the best defined line of demarcation between the 

 two generations, both on account of the redaction division, and 

 because preceding this division the mother-cell passes into a more 

 or less prolonged resting condition. It certainly represents the 

 greatest break in the continuity of the life-history." The seed 



