BARNES — NORTH AMERICAN MOSSES. V 



the Dominion of Canada. There is good reason to believe 

 that a majority of these are not well founded. 



It is, of course, true that species as such do not exist in 

 nature, and, therefore, that there will be diverse judgments 

 as'.to what individuals should be grouped to form a species. 

 But there is a general agreement that changes induced by 

 the immediate action of the environment upon the individ- 

 ual can not furnish a proper basis for specific distinctions. 

 Many of Kindberg's species are established upon such 

 slight differences in size, shape or habit as may readily be 

 induced by the immediate action of deficient or excessive 

 moisture, lij-ht or shade, etc. 



Other species are based upon wholly insufficient material. 

 When immature or barren specimens of Barhula and Bryum 

 are described as new species, one who knows the remark- 

 able variability of the vegetative parts of plants can not 

 but doubt the value of distinctions based upon them. Only 

 the repeated collection of barren specimens with some 

 persistent peculiarities can justify the establishment of 

 new species upon such material. 



Moreover, critical examination of Kindberg's new species 

 in several genera have been made by a number of bryolo- 

 gists, among whom may be named Mrs. Britton, Best, Grout, 

 Barnes, True, Cheney, Renauld, and Cardot. Without ex- 

 ception these students have declared a considerable num- 

 ber of the plants described as new to be referable to those 

 already described, of which they are either slight varieties 

 or forms unworthy a separate name. In a revision of the 

 genus Dicranum (ined.), for example, Barnes and True have 

 been compelled to reject seventeen out of eighteen species 

 described by Kindberg. 



These species are in many cases not only ill founded. 

 Few of the descriptions are either accurate or sufficient. 

 Very many are so brief and so purely comparative that 

 it is impossible to obtain a definite idea of the diagnostic 

 characters. 



