174 PLACODITJM. 



Virginia, TucJeerman Gen. 1872. Kansas, on limestone, Hall. 

 South Carolina (on rocks, and apparently now on dead wood), 

 Mavenel Texas, on limestone, Wright. California, on sand- 

 stone, Bolander. Varying considerably in the development of 

 the thallus, as above noted ; and the spores commonly longer in 

 the Californian plant. The black hypothallus, described by 

 Acharius, and Fries, is not always to be made out. 



12. P. microphyllinum, Tuckerm. herb. ; thallus squamulose ; 

 from dirty-greenish-yellow at length dirty-orange ; the adnate 

 scales crowded together into broken masses at the centre but 

 crenate-lobulate more or less at the circumference, bursting into, 

 and often concealed by heaps of yellow granules; apothecia 

 smallish, zeorine, adnate, flat ; dark- orange, the proper margin 

 sub-entire, the thalline one crenulate. Spores ellipsoid,^ mic. 



On dead wood common on the coast of New England. Penn- 

 sylvania, Dr. J. W. Eckfeldt. Illinois, Hall. Texas, Wright. 



California, Herb. Willey. Reminding one of the rupicoline 



P. aurantiacum, v. coronatum, Krempelh. (Hepp. n. 637. Ra- 

 benh. 723), but very different in fact in its more or less distinctly 

 lobulate thallus. The habitat is yet one deforming many lichens ; 

 but I know not where to refer the plant. 



13. P. citrinum (Hoffm.) Leight.; thallus effuse, minutely 

 ; granulose, conglomerate at length in areole-like masses ; lemon- 

 coloured ; on a white coanescent hypothallus ; apothecia small, 

 appressed ; disk waxy-yellowish and orange, the soon depressed 

 thalline margin sub-granulose, the thin, proper one often obso- 

 lete. Spores ellipsoid, ~ mic. Lecanora, Ach. Syn. p. 176, 



a. Callopisma, Koerb. Syst. p. 128. 



Lime-rocks, Neosho river, Kansas, Hall. Stones and mortar 

 in walls, Pennsylvania, Dr. J. W. Eckfeldt. 



14. P. aurantiacum (Lightf.) Naeg. & Hepp.; thallus un- 

 even and chinky becoming soon warted and wrinkled, and 

 broken at length into areoles ; lemon-coloured, pale yellow, yel- 

 lowish-gray, gray, or finally now white; bordered and decus- 

 sated by a blackening hypothallus, which is often obsolete; 

 apothecia almost middling-sized, sessile, zeorine, flattish ; the 

 orange, saffron, or tawny disk bordered by a thin proper mar- 

 gin, and a stouter, at length crenulate thalline one, which is 

 now obsolete, and the fruit then quite biatorine. Spores ellip- 



