135 



The treatment follows in general the lines noted already for the 

 first part. 



The reviewer, though claiming but a small fraction of the 

 knowledge of these plants possessed by Grout, finds himself on 

 general principles disagreeing in many, if not nearly all points. 

 A lengthy list of these points of difference would serve little 

 purpose; suffice it to say that one of them is the inclusion under 

 names of a great number of trivial "varities" and "forms," a 

 point upon which the author has especially "invited comment." 

 Such differences of opinion do not however prevent a cordial 

 welcome of this or any other equally competent revision of the 

 North American moss-flora, which is sadly in need of a good 

 many revisions. The European moss-flora, or more limited parts 

 of it, have already been revised by many bryologists, without 

 any general agreement on details having been arrived at, but 

 the result of it all is that the European moss-flora is at any 

 rate pretty definitely known, which is far from being the case 

 with that of North America, even if its tropics be excluded. 



In conclusion reference may be made to two very dubious 

 systematic inovations. The old Hypnum Schreberi, which has 

 become the step-child of recent taxonomy, is included by Grout 

 with Hypnum cuspidatum under the genus Collier gonella of 

 Loeske, which seems no improvement upon previous attempts 

 to find a place for it in the system. The exclusion of Ambly- 

 stegiella from the family Amblystegiaceae needs at least further 

 confirmation before it can qualify for general acceptance. 



A. LeRoy Andrews 



