168. Buellia ] 43. BUELLIACEAE 367 



A. On trees, old wood, over moss, and rarely on rocks 

 B. Thallus greenish gray to ashy 



C. Thallus more or less bordered by a black hypothallus 



D. Spores 1-septate 1. B. parasema 



D. Spores 2-3 -septate 1. B. parasema triphragmia 



C. Thallus without a black hypothallus 



D. Thallus scurfy or chinky, often disappearing 



E. Spores 8 in each ascus 11. B. punctata 



E. Spores 12-24 in each ascus 11. B. punctata polyspora 



D. Thallus minutely granulose 13. B.Elizae 



B. Thallus not greenish gray 

 C. Thallus whitish or ashy 



D. Spores 10-15 X 5-8 /* 12. B.conspirans 



D. Spores 19-30X7-11/* 15. B.dialyta 



C. Thallus not whitish or ashy or rarely so 

 D. Thallus chinky or minutely granulose 



E. Thallus ashy to brownish gray 14. B.Schaereri 



E. Thallus greenish straw-colored, granules more or 



less heaped 17. B. caloosensis 



D. Thallus squamulose or areolate 



E. Thallus squamulose, brownish to greenish brown ... 28. B. badia 

 E. Thallus areolate, brownish ashy to reddish or 



yellowish 21. B. turgescens 



1. Buellia parasema (Ach.) De Not., Giorn. Bot. Ital. 2 1 :198. 1846. 



Lichen parasema Ach., Lich. Suec. 64. 1798. B. disciformis (E. Fries) Mudd. 

 B. parasema var. microcarpa (Ach.) Koerb. B. siibdiscijormis (Leight.) 

 Jatta. 



Thallus continuous, smooth, becoming roughened, chinky and finally areolate, 

 greenish gray to ashy, darkening or yellowish, bordered more or less by a black 

 hypothallus; apothecia small to middle-sized, 0.3-0.8 mm. across, adnate to sessile, 

 rarely even more or less immersed, the disk flat to convex, black, the exciple black, 

 becoming flexuous, thin, and rarely disappearing; hypothecium dark brown; spores 

 oblong-ellipsoid, 10-22 X 5-10 /x. (Plate 45.) 



On trees, throughout the United States. 



var. triphragmia (Nyl.) T. Fries, Nov. Act. Reg. Soc. Sci. Ups. III. 3:327. 

 1861. 

 Lecidea triphragmia Nyl., Mem. Soc. Sci. Nat. Cherb. 5:126. 1857. B.lauri- 



cassiae (Fee) Mull. Arg. B. triphragmia (Nyl.) Arn. 

 Spores becoming 2-3-septate, and, on the whole, longer. 



On trees, from New England to Louisiana, and westward to California and 

 Washington. 



2. Buellia stellulata (Tayl.) Mudd, Man. Brit. Lich. 216. 1861. 

 Lecidea stellulata Tayl'., in Mack., Fl. Hibern. 2:118. 1836. 



Thallus thin, minutely areolate, gray to ashy white, the areoles flat or a little 

 convex, smooth, scattered or crowded into a chinky crust upon the black hypo- 

 thallus; apothecia minute, 0.15-0.25 mm. across, immersed to adnate, the disk flat 

 to somewhat convex, black, the exciple black, thin, infrequently and tardily dis- 

 appearing; hypothecium blackish brown; spores ellipsoid, 8-14 X 4-6.5 /x. 



On rocks, Massachusetts, New Jersey, Tennessee, Alabama, and California. 



3. Buellia halonia (Ach.) Tuck., Lich. Calif. 26. 1866. 

 Lecidea halonia Ach., Meth. Lich. 47. 1803. 



Thallus chinky to areolate, greenish yellow to grayish, areoles smooth, flat, 

 irregular, upon a black hypothallus; apothecia small to middle-sized, 0.4-1 mm. 

 across, adnate, the disk flat to strongly convex, black and more or less greenish 

 white pruinose, the exciple black, raised, thin, and disappearing; hypothecium 

 reddish-brown; spores ellipsoid, 11-16X6-8/*. 



On rocks, California. 



