114 GUIDE TO THE STUDV OF LICSENS. 



Spores two-celled, sometimes constricted, large, dark- 

 brown, 24/A X lliW" 



5. Buellia stellulata. Thallus of rather small, ir- 

 regular, scattered areoles. Apothecia very small, barely 

 extending above the surface of the thallus. Disk flat, 

 brown to black. Spores two-celled, not constricted, 

 ends blunt, 9/x X 5/x. 



6. Buellia Eiizce. Thallus of minute, more or less 

 scattered granules, gray to greenish. Apothecia medium. 

 Disk reddish-brown to black. Spores in various stages 

 of development, two-celled and dark-brown when ma- 

 ture, 13/x X 7/A. 



7. Buellia myriocarpa. Thallus thinly granular, 

 ash-gray to greenish. Apothecia small, numerous, 

 somewhat elevated above the thallus. Disk flat- 

 tened, black. Spores two-celled, dark-brown, 14/x 

 X 7/.. 



8. Buellia colludens. Thallus of very small, closely 

 adnate, angular squamules with slightly depressed mar- 

 gins, gray to brownish. Apothecia small, variable in 

 form, somewhat elevated above the thallus. Disk flat- 

 tened, black. Spores two-celled, constricted, dark- 

 brown, lo/x X 6.5/x. 



9. Buellia coracina. Thallus of comparatively large, 

 rather irregular squamules, with upper surface more or 

 less convex, dark to nearly black. Apothecia of me- 

 dium size, adnate upon the thallus. Disk convex, dark 

 to black. Spores two-celled, not constricted, dark- 

 brown, 15/x X 8yu,. 



10. Buellia hadia. Thallus of small, angular, closely 

 adnate squamules, tawny to brownish. Apothecia 



