GEKERA AND SPECIES. 113 



more or less irregular in outline. The spores are 

 normally two-celled, constricted at the middle, dark to 

 nearly black in color. 



The BuelUas have a wide range, and occur upon 

 rocks, rarely upon trees and old fences. They are 

 found at very high altitudes. Formerly the BuelUas 

 were united with the Lecideas. Reinke considers 

 them closely related to Rinodina, 



1, Buellia Schcsreri. Thallus granular to indis- 

 tinctly areolate, brownish. Apothecia very small. 

 Disk dark-brown to black. Spores two-celled, dark- 

 brown, not constricted, ends blunt, 12/x X 7yM. 



2. Buellia parmeliarum. Thallus granular, green- 

 ish to ash-gray. Apothecia small. Disk convex, 

 black. Spores oblong, dark-brown, 12/a X 5/x. 



This plant is said to be normally parasitic upon 

 species of Parmelia. The majority of plants found 

 upon Parmelia are, however, very likely parasitic 

 fungi, as in those examined no thallus could be 

 detected. 



S. Buellia parasema. Thallus granular to more or 

 less irregularly areolate, areoles sometimes scattered, 

 gray. Apothecia medium to large, considerably ele- 

 vated above the surface of the thallus. Disk flat- 

 tened, margin somewhat elevated, black. Spores 

 two-celled, dark-brown, not constricted, sometimes nar- 

 rowed at one end and slightly curved, 14ya X 6/x. 



4. Buellia dialyta. Thallus from thin and uni- 

 formly spreading to minutely granular, granules 

 often scattered, ash-gray. Apothecia small, somewhat 

 elevated above the thallus. Disk convex, black. 



