GENERA AND SPECIES. 107 



<J. Biatora vernalis. Thallus thin, granular, gray 

 to greenish. Apothecia variable in size, sometimes 

 in clusters. Disk yellowish to tawny, sometimes 

 black. Spores elliptical to oblong, often indistinctly 

 two-celled, colorless, 15/a X 7/x,. 



7. Biatora russiila. Thallus granular, ash-gray to 

 greenish. Apothecia small to medium. Disk flat or 

 convex, brick-red. Spores colorless, oblong, some- 

 times indistinctly two-celled, 11/t X 8.5/x. 



8. Biatora petiaspis. Thallus indistinct, dark-brown 

 to black. Apothecia medium size. Disk varying from 

 grayish to black. Spores variable in size and form, 

 simple, colorless, averaging 10/x X 4.5/x,. 



The hypothecium is often brown to dark in color, 

 perhaps never entirely black. 



9. Biatora parvifolia. Thallus usually distinct, 

 minutely thalloid or scaly, pale-green to yellowish- 

 green or even reddish-brown. Spores oblong, color- 

 less, simple, 14/x by 4/x. 



As the name (^parvifolia) indicates, this is in reality 

 a foliose lichen, but the lobes are so insignificant 

 that the average collector will take it for a crustose 

 lichen. 



10. Biatora granulosa. Thallus distinct, of gray- 

 ish-white, smooth wart-like elevations which often bear 

 greenish soralia.* Apothecia of medium size. Disk 

 convex, usually black, sometimes dark-brown or red- 

 dish. Spores variable in size and form, simple, color- 

 less or faintly yellowish-brown, IG/x X 7/x,. 



11. Biatora cinnaharina. Thallus granular, con- 



» Soralia are aggregates of soredi;i which may occur as circular or 

 linear patches. The word was iutroduced by Reinke (1895). 



