RECENT ADDITIONS TO OUR MOSS FLORA. 93 



broken up ; Hypniini alone beiiio; divided into 16 genera, a few, indeed, 

 truly natural, but others scarcely to be maintained on the slight cha- 

 racters assigned to thera ; for it is clear that a short or rostrate lid, a 

 smooth or rough fruitstalk, can only be of sectional importance, though 

 I am ready to admit that we may have genera of distinct habit and 

 appearance which it is most difficult to define on paper. 



Carl Milller, in his ' Synopsis Muscorum,' went too far in the oppo- 

 site direction, at least among the Pleurocarpi, and massed together 

 under Hypnnm and Neckera a host of species, differing widely in habit 

 and structure. His specific descriptions, however, are admirable, and 

 in both these works we find the areolation, or form of cells in the leaf, 

 taking a prominent place in diagnosis. Following these were the 

 valuable communications of Mr. Mitten, on foreign Mosses, to the 

 * Journal of the Linnean Society,' in which he proposed a classification 

 differing much from that generally accepted, and in which the modifi- 

 cations of the peristome hold quite a subordinate value in the construc- 

 tion of genera. 



Now it is evident that when we find the leaf-structure to be constant 

 in every Moss, and that many come before us only in the barren state, 

 we have far greater advantages for the identification and arrangement 

 of species, by characters derived from the leaf-cells, than by those 

 founded on the peristome, because they are obtainable at any time 

 during the existence of the individual. The majority of Mosses 

 have also a certain habit or facies associated with their distinctive 

 areolation, which readily enables us to refer them to their respective 

 families, as, e.g., the Bryacece, Fnnariacea, Bicranaceae. Having be- 

 stowed much thought on the subject, I feel bound to admit that I 

 consider Mr. Mitten's arrangement the most philosophical that has yet 

 appeared, and in fact one that will be more appreciated hereafter, be- 

 cause it is, so to speak, in advance of the time, few bryologists being 

 prepared to give up so much of the old views as to the value of the 

 peristome. As some may be unacquainted with it, I append an out- 

 line of the principal divisions. 



All Mosses are arranged in two suborders, Schistocarpi, comprising 

 Andrecea, and Stegocarpl, or those with a lid, and the latter of these 

 has two divisions, — Homodicfyi, with areolation of uniform cells, 

 and Heterodidyi, having two kinds of cells, and containing only the 

 genus Spluujmon. 



