GEOLOGY OF LA SALLE COUNTY. 



127 



T. concolor, (Dickson) Tuckerm. Thallus folia- 

 ceous, orbicular, g-reenish-yellow; divisions nar- 

 row, much dissected, beneath pale, fibrillose; 

 apothecia small, yellow or rufous. Spores nu- 

 merous. Physcia candelaria, N^d., etc. Occa- 

 sional on hickory, etc. 

 PARME:LIA, (Ach.) De Not. Thallus imbricate— 

 foliaceus, lobate or laciniate, appressed, mem- 

 branaceous, more or less fibrillose, sometimes 

 densely so, apothecia scutellseform, slig-htly ped- 

 icellate. Spores ellipsoid. 



P. perlata, (L.) Ach. 'Thallus g-reenish-g-lauces- 

 cent, or whitish; dilated, lobes rounded, often 

 sorediate, undulate, black beneath, with brown 

 maro-ins; apothecia small to larg-e, rufous, entire. 

 Ach. L. U. 459, etc. Found throughout our 

 county on oaks and other trees, and on boulders. 



P. perforata, (Jacq.) Ach. Thallus whitish, much 

 dilated; coriaceous, membranaceous, gflaucescent, 

 smooth, sinuate lobed; beneath black or fuscous; 

 fibrillose, apothecia very larg-e, perforate, cya- 

 thiform, disk fuscuous or rufous. Spores ellip- 

 soid. Common on trees. 



P. crinita, Ach. Thallus dilated; membranaceous, 

 surface covered with minute g-ranules and 

 branchlets; black beneath and fibrillose, lobes 

 ciliate; apothecia ample, cyathiform, disk 

 chestnut. Fr., L. E^., 58. On various trees. 



P. cetreta. Ach. Thallus greenish, dilated, rath- 

 er thin, smooth beneath black and hispid. The 

 sinuate lobes sorediferous on the margins, nar- 

 rowed, soon prolonged; apothecia medium size, 

 chestnut. Ach.-Syn., h. 198, etc. On trees and 

 stoms, 



P. tilliacea, (Hoffni) Fl. Thallus smooth, closely 



