^32 HOW TO KNOW THE MOSSES 



Plants growing in mats on the ground, on rocks, on trees, 

 and on decaying wood; light, dark or yellowish-green; 

 sometimes glossy; fruit common in some species. 



Stems usually prostrate or creeping; ascending in S. 

 arcuatus; pinnately or irregularly branched; branches lying 

 flat on opposite sides of stem; not cylindrical. 



Leaves curved, crow^ded ; usually large enough to be seen 

 except in S. reptilis; in most species turned in two opposite 

 directions, apparently in two rows, giving a flattened, 

 braided appearance along the stem and branches; in S. 

 arcuatus turned in one direction; light, dark or yellowish- 

 green; sometimes glossy. 



Seta /^-ij^ inches long; reddish-brown. 



Capsule long-cylindrical, except in S. curvifolius and S. 

 recurvans, inclined or nearly straight; mature in summer or 

 autumn. 



Operculum cone-shaped or short-beaked. 



The distinguishing characteristic of the mosses of 

 this group, with the exception of S. arcuatus, is the way 

 the lea'ues seem to part and curl in opposite directions, as 

 though growing in only two rows, giving a braided ap- 

 pearance along the stem and branches, which is very dif- 

 ferent from mosses with straight leaves arranged 

 equally, and with cylindrical branches. This generic 

 characteristic can usually be seen readily, but it is not 

 so easy to separate the species. 



In 5. arcuatus the leaves are curved and turned to 

 one side. 



