Lithodermeae. 197 



ANALYSIS OF THE GENERA. 

 Sect. LITHODERMEAE. 



Sub-sect. DiDYMEAE. 



Chondrioderma. Sporangia with a continuous porcelain- 

 like coat of lirae. 



DiDYMiUM. Sporangia with a pulverulent, crystalline coat 

 of lime. 



Lepidoderma. Sporangia with isolated, large patches of 

 lime. 



Spumaria. Aethalium consisting of sporangia arranged in a 

 dendritic manner. 



DiACHAEA. Sporangia iridescent, without lime. 



Sub-sect. Physarae. 



Badhamia. Threads of capillitium thick, containing lime 

 throughout their length. 



Craterium. Sporangia with a well differentiated lid, or 

 splitting in a circumscissile manner. 



Physarum. Capillitium with numerous large, irregular nodes 

 containing lime, and connected by thinner portions with- 

 out lime. 



TiLMADOCHE. Capillitium with small, scattered, elliptical 

 nodes containing lime internodes thin, elongated, with- 

 out lime. 



Leocarpus. Sporangia obovate, polished. 



Ceinkowskia. Capillitium with curved, free tips. 



Cratcriaclica. Columella present; threads of capillitium 

 mostly without nodes, containing lime. 



FuLiGO. A cake-like aethalium. 



Sub-sect. DiDYMEAE. 



Chondrioderma, Rost, (in part). 

 Sporangium stipitate or sessile, wall single or double, outer 

 wall charged with lime, perfectly smooth, porcelain-like, dehis- 



