238 HOW TO KNOW THE MOSSES 



72. ISOPTERYGIUM Mitt. (I-sop-te-ry-gi-um) 



A very large genus widely distributed. A few of the 

 most frequent species are given below. Name derived 

 from the Greek for " equal " and a '* little wing," 

 probably referring to the leaves lying flat on either side 

 of the stem. 



Plants small, growing in thin, flat mats on rocks, soil, and 

 decaying wood, usually in mountainous or hilly woods; 

 light or yellowish-green; often glossy; not common; fruit 

 rare except in /. turfaceum. 



Stems prostrate, irregularly branched, branches flattened. 

 Leaves straight; large enough to be seen, except some- 

 times in /. micans; rather separated, 

 wide-spreading; flattened on either side 

 of the stem, apparently in two rows; 

 light or yellowish -green; sometimes 

 glossy. 



Seta up to I inch long; reddish- 

 brown. 



Isopterygium turfaceum CapsuU long-cylindrical, inclined, 

 Portion of branch curved; reddish-brown ; mature in 



enlarged. ' 



summer. 

 Operculum cone-shaped or short-beaked. 

 Range, Canada, and south in the East to the Southern 

 States; Europe. 



The distinguishing characteristic of Isopterygium is 

 the flattened appearance of the plants due to the wide- 

 spread leaves lying flat, apparently in two rows on oppo- 

 site sides of the stem. This flattened appearance is also 



