284 



36. ACAROSPORACEAE [140. Acarospora 



C. Thallus distinctly areola te 



D. Apothecia more or less pruinose 



E. Thallus greenish brown 24. A. glaucocarpa verrucosa 



E. Thallus dark greenish gray to black 13. A. immersa 



D. Apothecia not pruinose 



E. Apothecia 0.1-0.2 mm. across 12. A. Heppu 



E. Apothecia 0.3-0.7 mm. across 17. A.arenosa 



B. Thallus more or less distinctly squamulose 

 C. Apothecia rarely more than 0.4 mm. across 



D. Apothecia minute, rarely more than 0.2 mm. across 



E. Apothecia brown 14. A. California 



E. Apothecia greenish or bluish pruinose 10. A. aeruginosa 



D. Apothecia rarely less than 0.2 mm. across 



E. Thallus light brown or white-pruinose 16. A. cineracea 



E. Thallus grayish white to light gray or brown . . IS. A. epilutescens 

 C. Apothecia rarely less than 0.4 mm. across 

 D. Apothecia rarely more than 0.6 mm. across 

 E. Apothecia more or less pruinose 



F. Thallus light brown 20. A. obpallens 



F. Thallus reddish brown 21. A. Carnegiei 



E. Apothecia not pruinose 



F. Thallus pale greenish gray to dusky yellowish or 



brown I 8 - A.Hassei 



F. Thallus light to blackish brown 26. A. molybdina 



D. Apothecia reaching 0.8-1.25 mm. across 

 E. Spores not more than 6 /a in length 

 F. Apothecia more or less pruinose 



G. Thallus yellowish brown to dark chestnut ... 19. A. cervina 



G. Thallus pale greenish brown 24. A. glaucocarpa 



F. Apothecia not pruinose 



G. Disk flat 22. A.squamulosa 



G. Disk rough and often papillose 23. A. fuscata 



E. Spores 8-15X7-10/* 25. A. glebosa 



1. Acarospora Schleicheri (Ach.) Mass., Ric. Lich. 27, f. 43. 1852. 



Urceolaria Schleicheri Ach., Lich. Univ. 332, 333. 1810. Lecanora Schleicheri 

 (Ach.) Nyl. 



Thallus of fairly conspicuous, sulphur-colored or finally dirty white, continuous 

 and areolate, convex, rugulose, sublobate squamules; apothecia small to middle- 

 sized, 0.3-1.2 mm. across, immersed 1 in a squamule, the disk flat, reddish brown 

 to brownish black, sometimes papillate, a crenate thalloid exciple sometimes visi- 

 ble; spores subspherical, 3-5 X 3 fx. 



On soil, Rocky Mountains and westward to California and Washington. 



2. Acarospora saxicola Fink; Hedrick, Mycologia 26:159. 1934. 



Thallus squamulose, the squamules small to middle-sized, irregular, sometimes 

 lobed, becoming imbricated and passing into a thick, irregular, areolate, grayish 

 or dirty white crust, more or less closely attached to the substratum; apothecia 

 small to middle-sized, 0.4-1.2 mm. across, immersed to adnate, 1 or more in an 

 areole or squamule, the disk flat to slightly convex, brown to brownish black or 

 grayish pruinose, the exciple thin, colored like the thallus, entire to slightly irreg- 

 ular and crenulate; spores spherical, 2.5-4.5//, in diameter, irregularly arranged. 



On rocks, Colorado. 



3. Acarospora reagens Zahlbr., Beih. Bot. Centralb. 13:162. 1902. 



Thallus whitish and white-pruinose, centrally areolate and marginally squamu- 

 lose, the squamules often scattered; apothecia immersed to semi-immersed, 1 or 

 more in each areole or squamule, middle-sized to large, 0.4-1.8 mm. across, the 

 disk flat, blackish red; spores spherical, 4-6 ^ in diameter. 



On sandy soil, southern California. 



4. Acarospora peltasticta Zahlbr., Beih. Bot. Centralb. 13:161. 1902. 

 Thallus of rounded or irregular, raised, dull ivory-white, chinky-areolate squam- 



