230 HOW TO KNOW THE MOSSES 



fruited specimen can be found, but the fruit is not 

 often found abundant. See Camptothecium (p. 243), 

 Thuidium ahietinum (p. 203), and Helodium (p. 205). 



70. PTILIUM (Sull.) DeNot. (Pti-li-um) 



A genus containing only one species. Name derived 

 from the Greek for '' feather," referring to the appear- 

 ance of the plants. 



Plants usually growing in loose mats on the ground, on 

 decaying logs, on earth-covered rocks, or at the base of trees 

 in mountainous or hilly woods; plume- 

 like; light green or yellowish-green; 

 fairly common; fruit occasional. 



Stems ascending or erect, sometimes 

 reaching 5 inches in length; regularly 

 and closely pinnately branched; branches 

 nearly equal in length except at the end 

 of the stems, where they gradually 

 shorten. 



Leaves strongly curved ^ small and fine, 

 but large enough to be seen when plants 

 are held to the light; not much changed 

 when dry; light or yellowish-green. 



Seta 1-1/4 inches long; yellowish- 

 or reddish-brown. 



Capsule long-cylindrical, inclined; 

 yellowish- or reddish-brown; mature 

 in autumn. 

 Operculum cone-shaped. 



Range, Arctic America, Canada, and the northern United 

 States, south in the East to North Carolina; Europe; Asia. 



Ptilium crista-castrensis 

 Branch enlarged. 



