360 41. CALOPLACACEAE [ 166. Caloplaca 



23. Caloplaca stillicidiora (Vahl.) Lynge, Vid. Skrift. Kl. 4. 1921. 



Lichen stillicidiorum Vahl., Fl. Dan. fasc. 18. pi. 1063, f. 2. 1792. Placodium 

 cerinum var. stillicidiorum (Vahl.) Willey. 



Thallus thin, light gray, scurfy-granulose to subsquamulose, becoming somewhat 

 scattered; apothecia small to middle-sized, 0.3-1.5 mm. across, sessile, the disk 

 flat to convex or somewhat wavy, yellowish green to dark olive, often white- 

 pruinose, the exciple light gray, raised, entire to wavy, sometimes radiately striate; 

 spores oblong-ellipsoid, 10-15 X 7-9 /x. 



On moss and soil, Massachusetts. 



24. Caloplaca Spaldingi Zahlbr., Ann. Mycol. 7:476. 1909. 



Thallus squamulose, lemon-yellow to orange, the squamules becoming crenately 

 lobed and more or less scattered; apothecia minute to small, 0.2-0.6 mm. across, 

 adnate to sessile, the disk flat to convex, orange to rusty brown, the exciple yellow 

 to orange, entire, sometimes raised; spores ellipsoid, 10-13 X 5-8 /x. 



On basaltic rocks, Arizona. 



25. Caloplaca pelodella (Nyl.) Hasse, Cont. U.S. Nat. Herb. 17:115, 116. 1913. 

 Lecanora pelodella Nyl., in Hasse, Lich. South. Calif. 10. 1898. 



Thallus thin, minutely squamulose, forming small, round to irregular, dark 

 greenish to brownish patches; apothecia small to middle-sized, 0.4-1.4 mm. across, 

 the disk flat to more or less convex, dark brown to dull black, the exciple moder- 

 ately thick, colored like the thallus, becoming wavy; spores oblong-ellipsoid, 10-12 

 X 5-6 ix. 



On granite rocks, southern California. 



26. Caloplaca atroalba (Tuck.) Zahlbr., Cat. Lich. Univ. 7:68. 1930. 

 Placodium atroalbum Tuck., Proc. Am. Acad. 12:172. 1877. 



Thallus crustose, closely adnate, chinky-areolate, yellowish brown, the areoles 

 sometimes obscurely lobed toward the margin; apothecia small to middle-sized, 

 0.4-0.8 mm. across, adnate, the disk flat to slightly convex, black, the exciple thin, 

 whitish or colored like the thallus, rarely flexuous; spores infrequently and obscure- 

 ly 1-septate, the cells polar, 14-24 X 5-8.5 /a. 



On rocks, Nebraska and Utah. 



27. Caloplaca fulgens (Swartz) Koerb., Abh. Schl. Ges. 31. 1862. 



Lichen fulgens Swartz, Nov. Act. Soc. Ups. 4:246. 1784. Placodium fulgens 

 (Swartz) Lam. & DC. 



Thallus thick, pale yellow, subfoliose, becoming wrinkled and areolate towards 

 the center, the margin crenately lobed, somewhat imbricated; apothecia minute 

 to small, 0.2-1 mm. across, sessile, occurring singly or in groups of two or more, 

 the disk flat to convex, rusty orange to reddish brown, the exciple lemon-yellow 

 to orange, wavy to crenate, finally disappearing; spores ellipsoid, 9-13 X 3-5 jx. 



On soil and rocks, from South Dakota and Nebraska northwestward to Mon- 

 tana, and in California. 



28. Caloplaca bolacina (Tuck.) Herre, Proc. Wash. Acad. Sci. 12:233. 1910. 

 Placodium bolacinum Tuck., Lich. Calif. 18. 1S66. 



Thallus well developed, tawny yellow, areolate-squamulose toward the center, 

 the margin subfoliosely lobed; apothecia minute to small, 0.2-1 mm. across, sessile, 

 the disk concave to slightly convex, tawny yellow to orange, the exciple of the 

 same color as the thallus, entire, disappearing; spores oblong-ellipsoid, 12-18 X 

 5-7 fi. 



On rocks and soil, California. 



