—49— 



cautious, debater in the arena of scientific discussion. On occasion he can be 

 blunt: e. g. when he criticises G. Roth's "Die Europaeischen Laubmoose. " 



The author's Introduction, alone, is a classic. Covering thirty pages, it 

 is more than merely an introduction; it is a learned review of existing moss sys- 

 tems, and a discussion of the basis of each view point, laying bare the foibles 

 and weak points of all; it is also a clear pointer in the direction of intelligent im- 

 provement. He here shows the importance, in elaborating a system, of attach- 

 ing equal importance to gametophyte and sporophyte. He brings to bear 

 upon the problems of relationship all past and current results of microscopic 

 and physiological study. He does more; he shows the importance of studying 

 mosses continuously in their living conditions in the field, season after season, 

 in . order to discover the influence of changing conditions of light and moisture 

 upon the various structures of the moss plant. In the body of the book numerous 

 instances are cited of the discovery of relationship, or even identity, of species, 

 especially of Sphagna and aquatic Hypna. 



Each of the 37 chapters is a rounded discussion of a moss group, a unit by 

 itself. It is unfortunate that the author disdained all headings; these and 

 brief analytical outlines, for chapters, would make the work more easy to use 

 in study and reference. As it is, the only convenience is an alphabetical list of 

 the genera and families of mosses discussed in the work, some 150 in number, 

 with page references. It would be well worth while to prepare also an alpha- 

 betical reference list of all the bryological authorities referred to in these trea- 

 tises, which show Dr. Loeske an exceptionally well informed student who de- 

 serves universal respect and consideration. 



The following passage translated from the Closing Word, shows fairly* well 

 the author's viewpoint in this work. Says the author, page 219: 



"More than ever does systematic bryology need to be lifted above the still 

 prevailing stage, of the mere descripcion of forms, — that (ancient) method which 

 is recognized by its fond appreciation of 'good' species, and in which the 'bad' 

 species, transitional forms and similar things are valued and represented as 

 'inconvenient for systematic purposes' (as is the case even in Limpricht), which 

 sounds almost as if the external finish of the systematic palace were the chief 

 thing. This trait, an heirloom from the times of 'absolute species' conceptions, 

 has for a long time after Darwin seriously jeopardized the progressive develop- 

 ment of systematic bryology. In the interests of 'types,' forms have been dis- 

 regarded more than was right, barring, however, certain 'excellent varieties.' 

 But even where forms were described, they were preferably disposed of as 'forms' 

 ■of the type. It is to just such matters that unequally greater attention will 

 need to be devoted (a course not to be confused with the uncritical making of 

 varieties). And, next to the morphology and phylogeny of a form, its biology 

 also is always to be taken into consideration. The growing insight into mosses 

 in all directions will necessarily advance the progressive development of system- 

 atic bryology beyond the boundaries set heretofore in large measure by morpho- 

 logical considerations, in order that the herbarium odor may be lost, and that a 

 ..little more of the life of the moss world may be mirrored in it." 



It is' impossible, in a brief review, to show up adequately the multitude 



