120. Psora] 33. LECIDEACEAE 215 



Thallus composed of middle-sized, ascending to erect, sometimes stipitate, 

 greenish gray to ashy squamules, the squamules dilated and lobed above or crowded 

 together into an irregularly folded crust; apothecia middle-sized to large, 0.8-2 

 mm. across, sessile, sometimes clustered, the disk flat to convex, reddish brown 

 to black, the exciple rather thick, lighter to finally black; hypothecium brownish 

 to dark brown; spores ovoid-ellipsoid, 7-13 X 4-6 /x. 



On soil and rocks, Sierra Nevada Mountains, California. 



12. Psora rubiformis (Wahl.) Hook, in J. E. Smith, Engl. Fl. 5:193. 1833. 

 Baeomyces rubiformis Wahl, in Ach., Meth. Lich. 324. pi. 7, f. 5. 1803. 



Lecidea rubiformis Wahl. Biatora globifera var. rubiformis (Wahl.) Torss. 



Thallus composed of middle-sized, rather thick, smooth, ascending, imbricated, 

 crenate or lobed, pale to darker fawn-colored, white-margined squamules; whitish 

 below; apothecia middle-sized to large, 0.8-1.8 mm. across, sessile, often clustered, 

 the disk strongly convex, purplish black to black, the exciple thin and disappearing ; 

 hypothecium brownish to brown; hymenium pale yellowish to brownish; spores 

 oblong-ellipsoid, 11-15 X 5-7 fx. 



On rocks and soil, Colorado, Washington, and California. 



13. Psora decipiens (Ehrh.) Hoffm., Descr. PI. Crypt. 2:63. pi. 43, f. 1-3. 1794. 

 Lichen decipiens Ehrh, in Hedw, Descr. Muse. Frond. 2:7. 1789. Biatora 



decipiens (Ehrh.) E. Fries. P. decipiens f. dealbata (Torss.) Mass. Biatora 

 decipiens f. dealbata Torss. Lecidea decipiens (Ehrh.) Zahlbr. 



Thallus composed of thin, small to middle-sized, closely adnate, round or 

 irregular and lobed, more or less concave, smooth or sometimes furrowed, rarely 

 clustered, flesh-colored to brick-colored or whitish, white-edged squamules; white 

 below; apothecia small to middle-sized, 0.3-1.2 mm. across, becoming sessile, 

 commonly borne along the margins of the squamules, the disk strongly convex, 

 brown to black, the lighter exciple thin, soon disappearing; hypothecium brownish 

 to brown; hymenium pale brownish; spores oblong-ovoid, 10-16 X 5-7 /x. 



On soil, throughout the United States except in the extreme southern part. 



14. Psora ostreata Hoffm, Deutschl. Fl. 2:163. 1795. 



Lecidea ostreata (Hoffm.) Schaer. Biatora ostreata (Hoffm.) E. Fries. 



Thallus composed of small, smooth, crenately lobed, imbricated, soon ascend- 

 ing, light to darker fawn-colored squamules; whitish and sometimes powdery 

 below; apothecia small to middle-sized, 0.6-1 mm. across, adnate, the disk flat, 

 black or more or less whitish pruinose, the exciple rather thick, grayish to black- 

 ening, becoming flexuous; hypothecium brownish to blackish brown; spores oblong- 

 ellipsoid, 8-10 X 2.5-3 ix. 



On old wood, Maine, Vermont, Colorado, Washington, and California. 



15. Psora lurida (Dill.) Lam. & DC, Fl. Fr. III. 2:370. 1815. 



Lichen luridus Dill, in Wither, Bot. Arr. Brit. PI. 2:720. 1776. Lecidea lurida 

 (Dill.) Ach. Biatora lurida (Dill.) E. Fries. 



Thallus composed of small to middle-sized, rather thick, closely adnate, round, 

 imbricated, irregularly lobed, greenish to dull lurid brown squamules; white below; 

 apothecia small to middle-sized, 0.5-1.4 mm. across, adnate, sometimes clustered, 

 the disk flat to convex, reddish brown to black, the exciple thin, brown to black, 

 soon disappearing; hypothecium brownish to brown; spores oblong-ellipsoid, vary- 

 ing toward ovoid, 12-15 X 5-7 /a. 



On rocks, Michigan, Colorado, Washington, and California. 



16. Psora globifera (Ach.) Mass, Ric. Lich. 91. f. 186. 1852. 

 Lecidea globifera Ach, Syn. Lich. 51. 1814. Biatora globifera Ach. 



Thallus composed of middle-sized to large, thick, smooth to slightly rough and 

 chinky, irregularly lobed. often imbricated, greenish gray to reddish brown, as- 

 cending squamules; paler or white below; apothecia small to middle-sized, 0.5-1.5 



