The Horn-tooth Mosses 



Pedicel. Slender, wine-red, erect. 



Lid (operculmn). Conical, short-beaked. 



Teeth (peristome). Purple, each split into two equal, strongly 

 cross-barred segments, with tiny projections toward the apex. 



Annulus. Large, rolling back as the lid falls. 



Spores. Mature in early spring, when they are ousted by the 

 shrinking of the wall tissue. 



Veil. 



Spore-case with 

 veil. 



Spore-case. Annulus. 



C. piirpiireum. 



Portion of 

 peristoms. 



Distribution. Almost universal. 



Variety Xanthopous. Greek gavflos, yellow, and 7roO<?, a foot; 

 has a pale-yellow pedicel. 



Variety Aristatus. Latin "awned"; has the spore-case and 

 pedicel pale and the mid-vein of the leaf extending beyond the 

 apex of the leaf blade. 



Variety Minor. Latin "smaller"; is said to have narrower 

 teeth jointed only from the middle downward. 



Genus POTTIA, Ehrh. 



The species of this genus are small and grow in tufts or 

 cushions on the ground or in crevices of rocks. The stems are 

 simple or sparingly branched from the base. The 

 leaves are oval to oblong and obovate, soft, opaque, 

 smooth or covered with tiny projections; 

 the apex is usually taper-pointed, or 

 hair-pointed ; the base transparent ; the 

 vein round in section. 



The cylindrical to obovate spore-case 

 has sometimes a very short pedicel and 



169 



P. truncata. Leaves. 



