The Genus Hypnum 



Calliergon. Large plants with stem erect or inclined and 

 with few cylindrical branches ; leaves very concave, mem- 

 branous, round to oblong or heart-shaped ; cells very com- 

 pact, narrow, alar cells inflated ; spore-case oblong, horizontally 

 curved. 



Leaves. 



Spore-cases. 

 Calliergon: Hypnum Schreberi. 



Pleurojium. Plants feather-like, branches twice to three 

 times divided ; leaves membranous, shining ; veins short, single 

 or double; paraphyllia numerous; cells 

 linear, uniform ; spore-case short, egg- 

 shaped ; lid beaked. 



Hylocomnhtm. Plants of large size with 

 few irregular branches, or sometimes more 

 or less feather-branched. Leaves widely 



Paraphyllia. 



Spore-case. 



Pleurozium; Hypnum splendens. 



279 



Leaf. 



