MOSSES \\ II II A HAND-] ENS 



THE GRIMMIA FAMILY 



i; 



THE Grimmias and their allies constitute a large family of 

 mosses characterized by their very dark color, setae 

 so short that the capsule is often not exserted, and by 

 other characters that are microscopic. They are blackish, or 

 brownish green, sometimes hoary by reason of the colorless leaf 

 apices. They grow almost exclusively on stones and bark of 

 living trees. Some are aquatic, growing on stones in swift brooks, 

 but most grow in dry situations, during a dry period becoming so 

 dry and brittle as to crumble in the fingers, but taking advantage 

 of every rain to start up their growth with renewed energy. 



Some of the most common and conspicuous members of this 

 family are Hedwigia, Drummondia, Weissia, Grimmia, and 

 Orthotrichum. The last two are too difficult to treat here. 



DRUMMONDIA 



Fig. 15. Drummondia prorefens. 



a x'i. b x 10. c, Calyptra • 10. d, 

 Empty capsule ;•; 10. 



DRUMMONDIA is a com- 

 mon moss of the Grim- 

 mia family. It always 

 grows on the bark of trees, but 

 is easily distinguished from its 

 tree-growing allies by three 

 characters: Its steins arc long 

 and closely applied to the bark 

 of the tree, sending out short 

 horizontal branchlets so thickly 

 that the stems below become 

 apparent only when the plant 

 is removed. The capsule is on 

 a long seta, and the calyptra is 

 cucullate. 



Drummondia is named for 



Drummond, one of the earliest 

 collectors of American mosses. 

 Our only species is A pror}- 

 pens (Hedw.) E. G. Britton. 

 {/>. clave I lata Hook). 



