72 LTCHENES. 



Table of the Genera. 



A. Apothecia none. 



1. Lepraria. TJiallus erustaeeo-leprose, uniform effuse. 

 Apothecia none. Gongyli covering the thallus, more or less 

 scattered, naked. 



2. Spiloma. Thallus crustaceous, uniform, effuse. Apo- 

 thecia none. Gongyli collected into compact masses, coloured, 

 naked. 



B. Apothecia stalked. 



* Stipulate ; or apothecia with stalks of a proper substaiice. 



3. Calictum. Thallus crustaceous, uniform. Apothecia 

 goblet-shaped, more or less stipitate, marginate, enclosing a 

 powdery mass. 



4. B-EOMYCEs. Thallus crustaceous, or filmy, uniform. 

 Apothecia convex or orbiculate, not bordered, on solid, soft 

 foot-stalks. 



* * Apothecia on podetia, or stalks formed of the thallus. 



5. Cenomvce. Thallus cartilagineo-crustaceous, or folia- 

 ceous, laciniated ; podetia fistulose, sterile, or bearing apothecia 

 on their summits. Apothecia hemispherico-subglobose, not 

 bordered, fixed by the circumference. 



* * * Apothecia on the sublinear branches of a snberect thallus. 



■f Apothecia internally pulverulent. 



6. Sph^rophon. Thallus crustaceo-cartilaginous, branched, 

 solid within. Apothecia subglobose, terminal, formed of tlie 

 thallus, enclosing a black powdery mass, bursting with a torn 

 margin. 



f f Apothecia internally solid. 



1 . Apothecia turbinate, at length globose. 



7. Stereocaulon. Thallus dense, nearly woody and 

 branched, or crustaceous. Apothecia stalked, turbinate, solid, 

 marginate, at length hemispherico-globose, their margin evanes- 

 cent. 



2. Apothecia discoid. 



a. Thallus compressed. 

 8 Evernia. Thallus subcrustaceous, branched and laci- 



