REVIEWS 357 



said to have culminated in the publication, during the latter half of last century, 

 of De Bary's Vergleichende Anatomic. The results accomplished had to a large 

 extent been ignored by purely systematic botanists, and there can be little doubt 

 that in many herbaria at the present day the anatomical and physiological aspects 

 of the questions at issue receive comparatively little consideration. But although 

 such is the case, the fact must not be lost sight of that the importance, or at any 

 rate the desirability of the use of anatomical characters in taxonomic work had 

 been very early recognised by some systematists, among whom may be mentioned 

 Linnreus himself. Moreover, certain anatomical evidence has been long employed, 

 consciously or unconsciously as such, by systematists in arriving at their conclusions, 

 and in this connection we need only mention the fundamental anatomical difference 

 implied in the use of the terms " exogen " and " endogen " in distinguishing the 

 two great classes of ordinary flowering plants ; the recognised importance of the 

 presence or absence of endosperm ; and the occurrence in the plant of resin-con- 

 taining glands. And it must be admitted that, in its essentials, the question is one 

 of degree ; for while it is obviously convenient to base the description and classifi- 

 cation of plants upon characters which are more or less readily visible to the naked 

 eye, i.e. upon general external characters, it by no means follows that characters 

 involving the use of the microscope and histological methods are of any less value 

 for taxonomic purposes. It was a realisation of this truth which led Radlkofer in 

 1883 to express his opinion that, in coping with the problems of systematic botany, 

 "the next hundred years will be devoted to the anatomical method"; and 

 Solereder has informed us that the prediction of Radlkofer was directly responsible 

 for the compilation of this work towards which his own researches have contributed 

 so largely. 



The book deals with the Dicotyledons alone among the Phanerogams, and the 

 classification adopted is that of Bentham and Hooker. Up to the present, the first 

 volume only has been completed by the translators, and this comprises Solereder's 

 Introduction, and the survey of the polypetalous and gamopetalous orders ; the 

 author's valuable Concluding Remarks, in which he summarises the case for the 

 anatomical method, have thus not yet appeared. The simple plan of the work 

 renders its contents very easy of access. The description of each natural order 

 opens with a general view of its essential anatomical features, followed by a detailed 

 account of the structure of the plant body, arranged under the headings of "Structure 

 of the Leaf" and " Structure of the Axis." It will be readily understood that the 

 amplitude of the descriptions of the different orders varies greatly, depending 

 entirely upon the amount of work which has been done upon them by anatomists. 

 Further, the structure of the vegetative organs alone is considered, and of them 

 practically the whole of the work is concerned with the leaf and stem, the former 

 having been found to possess, in the character of its stomata, hairy coverings, and 

 secreting sacs, features of great taxonomic value. A chronological series of 

 references to literature is given at the end of the description of each order, and in 

 the English edition special efforts have been made to bring the bibliography down 

 to the most recent times. 



In reviewing the claims of the anatomists, the question naturally presents itself 

 as to how far the method advocated has been successful in taxonomic research. In 

 his Introduction Solereder emphasises the extreme caution which must' be exer- 

 cised in basing opinions upon anatomical (endomorphic) as opposed to external 

 (exomorphic) characters. He points out the distinctions which must be drawn 

 between characters which can only be explained as hereditary characters, the 

 origin of which is lost, and those which are regarded as a result of adaptation to 



