204 HOW TO KNOW THE MOSSES 



Plants Jem-like, growing in intricate mats on the ground, 

 decaying wood, and rocks in moist woods; bright green or 

 yellow-green ; common ; fruit occasional. 



Stems long, prostrate, or often alternately arched and 

 rooting; regularly hipinnately branched; occasionally some 

 branches are tripinnate, especially toward the base near the 

 main stem, giving a triangular appearance to the branch as 

 a whole. 



Leaves straight, too small to be seen. 



Seta long, i-i>^ inches; reddish. 



Capsule long-cylindrical, inclined, curved; reddish- 

 brown; mature in winter. 



Operculum short- or long-beaked. 



Range, almost cosmopolitan. 



The regular hipinnate branching of these two Thuid- 

 iums gives them a delicate, fern-like appearance, which 

 is a conspicuous characteristic. 



Another fern-like moss isHylocomium (p. 225), but it 

 is much larger than Thuidium, and is more often tri- 

 pinnate in branching. An unusually large growth of 

 Thuidium, especially if the tripinnate branching is 

 conspicuous, may be mistaken for Hylocomium. In 

 this case the general manner of growth must be care- 

 fully examined. In Thuidium the stems interweave 

 and often arch and root again at the tips, then con- 

 tinue growth, arching and rooting and so on, forming a 

 tangled mat, so that it is difficult to pull out a long 

 piece of the stem. The new growth does not regularly 

 start from the center of the shoot of the previous year, 

 as in Hylocomium. On the other hand, the tips of the 



