22 THE CHICAGO ACADEMY OF SCIENCES. 



27. P, tfibacia, (Ach.) Tuckerm. .Thallus smallish, membranace- 

 ous, sub-stellate, glaucescent; beneath white, fibrillose; lobes 

 short, appressed; margins erose, granulate; apothecia small, 

 sessile, black or pruinose, margin sub-entire. Lecanora, Ach. 

 S. L. 191. Tuck., etc. 



On elms at Glencoe, and in other locaHties on hickory. 

 A variety of P. stellaris, (d.) of Tuck. Syn., 75. 



28. ?, obscura, (Ehrh.) Nyl. Thallus stellate, orbicular, appressed, 



epruinose, glaucous, fuscescent, beneath black, fibrillose, lobes 

 many-cleft, flatish; ciliate; apothecia rather small; disk nigro- 

 fuscous, margin entire. Spores bilocular. Th. Fr., Scand. 142. 

 Harmeha, Fr. L. E. 84. 



On hickories and other trees in west part of Cook County; near 

 Lemont and Joliet on trees and calcareous rocks. Quite 

 variable everywhere, having several forms. 



29. P, adglutinata, (L.) Nyl. Thallus often slightly ohvaceous, also 

 cinerascent and brown, adheres closely to substrate, small; 

 lobes thin, flat, compaginate; apothecia small, disk nigro- 

 fuscous, margin entire. Nyl. Syn. 438, etc. 



On elms and hickories in Cook and Will Counties. This is a 

 well marked species. 



30. P, gfanulifera, (Ach.) Tuckerm. Thallus glaucescent and 

 white, pruinose, be-sprinkled with powdery granules; beneath 

 pale, corticate, fibrils black; lobes multifid, dentate-crenate; 

 apothecia small, inflexed margin crenate. Parmelia, Ach. 

 Syn. L. 212. Tuckerm. Obs. 890. 



Found on hickories near Elgin and at Lemont. A variety 

 of P. speciosa (e. of Tuck.), but quite marked. 



FAMILY 3. PELTIGEREI. 



Peltigera, (Willd. , Hoffm.) Fee. Thallus membranaceous, lobate, 

 frondose, foliaceous; beneath somewhat villous, marked with 

 veins, occasionally cyphels; apothecia peltseform. Spores 

 fusiform. Cortical layer, in some species consisting of 

 gonidia, in others, of gonimia. 



