26 THE SPHAGNA CE^, OR PEAT-MOSSES OF 



Wilson, in Bryologia Brit. (1855), arranged them somewhat 

 as Bridel. 



1. Leaves obtuse, rounded, or elliptic. 



S. cymbifolium, compactum, molluscum, rubellum. 



2. Leaves acuminate, ovate or ovato-lanceolate. 

 a. Leaves erecto-patent. 



S. acutifolium, fimbriatum, cuspidatum, contortum. 

 aa. Leaves squarrose. 

 6". squarrosum. 

 Sullivant, in his Mosses of the United States (1856), forms 

 four groups, characterized by the relative position of the cells in 

 the branch leaves, as seen in transverse section — a valuable 

 distinction, no doubt, but far too minute and difficult of obser- 

 vation to be of practical utility. 



1. Chlorophyllose cells entirely enclosed by the hyaline, and 

 not reaching either surface of leaf. 



S. cymbifolium, compactum, contortum, Lescurii, tenerum, 

 humile, cyclophyllum, sedoides. 



2. Chlorophyllose cells oval, reaching to both surfaces of leaf. 



■S". squarrosum, macrophylhim. 



3. Chlorophyllose cells triangular, placed between the hyaline 

 at the concave or inner surface of leaf. 



S. acutifolium, fimbriatum, tabulare, molle. 



4. Chlorophyllose cells triangular, placed between the hyaline 

 at the convex or outer surface of leaf. 



S. cuspidatum, Torreyanum. 



Schimper, in his monograph, divides the species into two 

 groups — monoicous and dioicous — a plan of very little practical 

 help, since it is of no use with plants in a barren state. The same 

 arrangement is followed in the Synopsis Muse. Europ. ed. 1 

 (i860). 



C. Hartman, in the eighth edition of the Scandinavian Flora 

 (1861), uses the stem leaves for this purpose, thus : — 



1 . Apex of cauline leaf broad, strongly and distinctly fimbriate 



in its whole margin. 



6". cymbifolium, Angstrbmii, Lindbergii, fimbriatum. 



2. Apex indistinctly fimbriate or lacerate. 



S. rigidum, squarrosum, subsecundum, teres. 



3. Apex with a few distinct teeth, not fimbriate or lacerate. 



S. acutifolium, Miilleri. 



