138. Biatorella ] 36. ACAROSPORACEAE 281 



spread, sometimes scurfy and chinky, grayish green, varying toward whitish or 

 brownish, rarely disappearing crust; apothecia minute, 0.2-0.4 mm. across, adnate, 

 the disk flat to slightly convex, light brown to black, the exciple soon covered; 

 hypothecium hyaline; spores spherical, 1.5-3/* in diameter. 



On trees, Massachusetts, Minnesota, Washington, and California. 



7. Biatorella testudinea (Ach.) Mass., Ric. Lich. 131. f. 258. 1852. 



Lecidea fumosa var. testudinea Ach., Vet. Akad. Nya Handl. 232. 1808. Leci- 

 dea morio E. Fries. Lecidea morio var. coracina (Hoffm.) Schaer. 



Thallus well developed, of yellowish copper-colored and blackening, flat or 

 slightly convex, marginally lobed areoles, resting on or more or less immersed in 

 a black hypothallus; apothecia minute to middle-sized, 0.3-1 mm. across, partly 

 or wholly immersed, round to irregular, the disk flat to convex, black, the exciple 

 black, becoming indistinct; hypothecium hyaline to dark reddish brown; spores 

 spherical to ellipsoid, 3-5 X 2-3 /a. 



On alpine rocks, the White, Rocky, and Sierra Nevada mountains. 



8. Biatorella campestris (E. Fries) T. Fries, Gen. Heterol. Eur. 86. 1861. 



Biatora campestris E. Fries, Vet. Akad. Handl. 1822:273. 1822. 



Thallus scattered and inconspicuous, pale greenish, fading to whitish, scurfy- 

 granular, disappearing; apothecia minute or small, 0.2-0.5 mm. across, sessile, the 

 disk concave to slightly convex, amber-colored to reddish black, slightly white- 

 pruinose ; hypothecium hyaline ; spores oblong-ellipsoid, 5-8 X 2-3 /*. 



On soil, mosses, and old wood, from Massachusetts to New Jersey, and west- 

 ward to Illinois. 



9. Biatorella fossarum (Nyl.) T. Fries, Lich. Scand. 2:397. 1874. 



Lecidea fossarum Nyl., Ann. Sci. Nat. III. 20:320. 1853. Biatora fossarum 

 Mont. 



Thallus scurfy, greenish gray, thin and disappearing, or compacted into an 

 uneven crust; apothecia small, 0.7-1 mm. across, adnate to sessile, the disk convex 

 to hemispherical, pale yellow to reddish brown; exciple soon disappearing; hypo- 

 thecium yellowish brown; spores oblong to oblong-cylindrical, 7-11 X 3 /*. 



On soil, New Jersey, Florida, Illinois, and Washington. 



10. Biatorella clavus (Lam. & DC.) T. Fries, Lich. Scand. 1:409. 1874. 

 Patellaria clavus Lam. & DC, Fl. Fr. ed. 3. 2:348. 1805. 



Thallus inconspicuous and evanescent, sometimes seen under the apothecia; 

 apothecia middle-sized to large, 0.7-2 mm. across, sessile to substipitate, scattered 

 or clustered, round or variously irregular, the disk dark red to black, concave to 

 slightly convex, the exciple thick, often chinky and wrinkled, or finally disappear- 

 ing; asci cylindrico-clavate, often saccate; hypothecium hyaline to pale brown; 

 spores oblong-ellipsoid, 4-6.5 X 2 /*. 



On rocks, from New England to Georgia, and westward to California. 



11. Biatorella simplex (Dav.) Branth & Rostr., Bot. Tidssk. 3:241. 1869. 

 Lichen simplex Dav., Trans. Linn. Soc. Lond. 2:283. pi. 28, f. 2. 1794. Lecanora 



privigna (Ach.) Nyl. 



Thallus thin and evanescent, seldom seen ; apothecia minute to small or middle- 

 sized, 0.2-1 mm. across, adnate, scattered or crowded, round to irregular, the disk 

 brownish to black, reddish when wet, the exciple raised, black; hypothecium hya- 

 line to yellowish; spores oblong-ellipsoid, 3-6 X 1-1.5 /x. 



On rocks, throughout the United States. 



var. pruinosa (Ach.) Fink, Cont. U.S. Nat. Herb. 14:66. 1910. 

 Lichen pruinosus Ach., Lich. Suec. Prod. 77. 1798. Lecanora privigna var. 

 pruinosa (Ach.) Tuck. Lecidea albocoeridescens var. immersa E. Fries. 

 B. pruinosa (Ach.) Mudd. 

 Thallus thin; apothecia middle-sized, 0.8-1.3 mm. across, partly immersed in the 

 substratum, the disk whitish or grayish pruinose. 

 On rocks, throughout the United States. 



