THE LICHEN-FLORA OF CHICAGO AND VICINITY. 21 



22. -P, conspersa, (Ehrh.) Ach.. Thallus straw-colored, greenish, 

 laciniate, much divided, appressed, often isidiophorous in the 

 centre; beneath fuscous-black, sparingly nigro-fibriliose; lobes 

 sinuate, often crenate, or pinnatifid, complicate; apothecia 

 large, chestnut, margin subcrenulate. Spores ellipsoid, simple. 

 Ach. L. U. 486. Muhl. Catal. 1818 Tuckerm. Syn. G4, etc. 

 In Lemont and Will County on stones; also found near Elgin 



on old wood. This species has a wide distribution in the 



United States. 



23. P, colopodes, (Ach.) Nyl. Thallus coriaceous, glaucescent, be- 

 neath dark brown, spongy nap, with a few fibrils; lobes sin- 

 uate-cleft, flat; apothecia large, disk chestnut. Spores numer- 

 ous.- Tuck. Syn. 61; Nyl. Syn., etc. 



On oaks near Lemont. There is a very narrow lobed form not 

 as yet observed here. 



Physcia, (D. C, Fr. ) Th. Fr. Thallus foliaceous, variously 

 divided, stellate, somewhat fibrillose; apothecia scutell^e- 

 form. Spores ellipsoid, bilocular. 



24 . P, speciosa, (Wulf.) Nyl. Thallus greenish, glaucous, loosel}^ 

 stellate, appressed, beneath corticate, rhizinae whitish; lobes 

 sinuate, flat, pinnatifid, with powdery margins; apothecia me- 

 dium size, sessile, margin crenulate; disk fuscous. Spores 

 bilocular. Parmelia speciosa, Ach. L. U. 480; Fr. L. E. 80; 



," Tuck. exs. n. 81] Calkins exs. 



Occurs at Riverside on oaks; on hickories, near Elgin and 

 other localities. 



25. P, stellaris, (L.) Nyl. Thallus albo-glaucescent, stellate, ap- 

 pressed, orbicular; beneath pale, fibrillose, lobes linear, many- 

 cleft, compaginate, or discrete; apothecia small, sessile; 

 disk fuscous-black, often grey-pruinose, margin entire or 

 crenulate. Parmelia, Fr. L. E. 82. 



This, the most common species of the genus, occurs every- 

 where on oaks, hickories and other trees, as well as on rocks. 



26. P, stellafis, (L.) Nyl., var. aipolia, Nyl. Thallus brown be- 

 coming blackish, beneath black, fibrils hispid; apothecia sub- 

 crenate, Nyl. Scand., 111. Parmelia, Ach, S. L. 215. 

 Found on boulders of the prairies and on stones at Lemont . 



