CRYPTOGAMIA ALG^. 823 



Inflated Lichen. Anglis. 



Upon the trunks of old trees, upon rocks, and 



fometimes upon the ground. 

 The leaves are laxly imbricated, and frequently 

 grow in a circle. They are varioufly divided, 

 and terminated with obtufe bifid, and fometimes 

 palmated, lobes ; their upper furface convex and 

 white, their under one black and fmooth. But 

 what diftinguifhes this Lichen more particularly 

 is, that all the leaves and their legmenrs are hoi- 

 low, or compofed of two membranes, a little 

 diflant from each other. The extremities of 

 the legmen ts in the younger leaves are in Hated, 

 the membranes which compoi'e thcrn beln'- 

 united at the end, fo that if thofe extremitiej; 

 are cut tranfverfely with a penkfiife, the two 

 membranes will be dillindlly feen, and a cavity 

 between them. 

 The extremities of the old leaves are open, and 

 the upper membrane a little extended, waved 

 on the edges, and covered with a white farina- 

 ceous powder; fometimes alfo the edges of all 

 the fegments are covered with the like powder. 

 This is probably one of the fexes, as, accord- 

 ing to Dillenius^ it does not produce fliields. 

 Other fpecimtrns, which have no powder, produce 

 fliields or a reddilli brown ctjjour, Itandino- oxi 

 very fliort footftalks, their ouifide of the coioiLir 

 of the leaves. I'heic ihields are feldom to be 

 ■ .tbi;nd, _'\\ ■■'■•■ '; 



L: im- 



