EUROPE AND NORTH AMERICA. 25 



CHAPTER V. 



ARRANGEMENT OF THE SPECIES. 



It is always convenient to distribute the species of a genus into 

 groups or sections, especially when they happen to be numerous 

 and difficult of diagnosis ; this has been attempted with respect to 

 the Sphagna in various ways by different authors, and it may be 

 of advantage to present an outline of each of these. 



Bridel, in his Bryologia Universa (1826) arranged his sixteen 

 species as follows, classing them as Musci Evaginulati Cladocarpi : — 



1. Ramuli distinctly fasciculate. 



a. Leaves broader, rather obtuse. 



6\ cymbifolium tenelhcm,squarrosum, contortion, subsecuu- 

 dum, immersum, oblongum, macrophyllum, denticulatum. 



b. Leaves narrower, rather acute. 



S. capillifolium, recurvum, cuspidatum. 



2. Ramuli indistinctly fasciculate. 



6". compactum, ericetorum, condensatum, subulatum. 

 C. Muller, in his valuable Synopsis Muscorum (1848), made a 

 great advance on the writings of previous authors by introducing 

 the cell structure of the leaves into the specific character of these 

 mosses. He points out the differences in the leaves of the stem, 

 branches, and peduncle, and the presence or absence of spiral 

 fibres in them. 



1 . Leaves without annular fibres. 



S. sericeum, macrophyllum. 



2. Leaves with annular fibres. 



a. Leaves rounded at apex. 



6". cymbifolium, &c. 



b. Leaves truncate. 



* Peduncular leaves without spiral fibres. 



6". molluscum, squarrosum, cuspidatum, acutifolium, &c. 

 ** Peduncular leaves with spiral fibres. 



6". laxifolium, compaction, molluscoides,subsccuudum, &c. 

 All the species are said erroneously to be dioicous. 



