GENERA AND SPECIES. 117 



southern in their range. They occur upon trees and 

 mosses. 



1. Lopadium pezizoideum. Thallus granular, uni- 

 formly spreading, thin, grayish. Apothecia of medium 

 size, discoid, not numerous. Disk convex, dark. Spores 

 large, one in each spore-sac, colorless, and simple in 

 early stages of development, multilocular and dark 

 when mature, 90/x X 35/a. 



13. Gyalecta. 



This is one of the older genera, and hence it would 

 bfi reasonable to assume that it is well understood, but 

 such is not the case. A large number of herbarium 

 specimens labelled as Gyahctas belong to other gen- 

 era. It is in fact impossible at the present to give 

 the exact limitations of the genus. The following 

 are some of the generic characters, as far as they 

 could be determined. 



The thallus is crustose in the majority of species ; 

 becoming minutely foliose in the higher species, 

 color generally dark. The algie are Protococcus, 

 Apothecia are discoid. Disk is flattened to some- 

 what cup-shaped, dark. The hypothecium is usually 

 colorless. The spores are quite large and multilocu- 

 lar, oblong to spindle-shaped, usually colorless, though 

 some are evidently dark in color. 



They occur upon rock and trees. Nothing definite 

 can be stated as regards range and frequency of occur- 



rence. 



1. Gyalecta cupularis. Thallus crustose, evenly 

 spreading, gray to dark. Apothecia discoid. Disk 



