106 GUIDE TO THE STUDY OF LICHENS. 



irregular margin. Disk yellowish to brown. Spores 

 ovoid or nearly spherical, colorless, 7fx to 1 Ofx. 



This species has many characters peculiar to the 

 lower Lecanoras, which would make it seem proper to 

 place it with that group. 



2. Biatora myriocarpoides. Thallus thinly crus- 

 tose and of a dark muddy color. Apothecia small, 

 sessile. Disk flat or slightly convex, dark. Spores 

 elliptical, colorless, 8.5//, to 9/x. 



The hypothecium is generally dark or even black, 

 which would point toward the Lecideas ; but the 

 color variations of the hypothecium are, however, 

 too great to be reliable as a generic character. 



3. Biatora uliginosa. Thallus consists of minute 

 granular elevations, color varies from gray to dark or 

 black. Apothecia small, few in number. Disk flat- 

 tened, sometimes convex, dark color. Spores ellipti- 

 cal, colorless, rarely two-celled, 22/a X 8/x. 



Jf. Biatora contigua. Thallus evenly spreading, 

 scaly or squamose, light-gray. Apothecia compara- 

 tively large, numerous, sessile. Disk convex, some- 

 times flattened, black with a translucent white film 

 which is characteristic of the species. Spores ellip- 

 tical, colorless, 22^ X ^/x. 



5. Biatora diapensice. Thallus rudimentary, color 

 whitish. Apothecia of medium size. Disk generally 

 convex, reddish-brown or black. Spores colorless, 

 elliptical, 10/i, X 3.5yu,. 



The hypothecium is occasionally blac^:, and this 

 plant may, therefore, be mistaken for a species of 

 Lecidea. 



