GENERA AND SPECIES. 197 



Cyphella.) There are, however, exceptions (Sticta 

 amplissima, S. pulmonaria, and several others). 



The apothecia are rather small, discoid, sessile. 

 Disk slightly concave, flattened to slightly convex. 

 Spores colorless, oblong to acicular, four-celled. 



The species are southern in their range, they occur 

 upon trees and rocks. 



1. Stictina tomentosa. Thai! us medium, deeply 

 lobed, pitted above and bluish-brown, paler beneath, 

 with white cyphella3 and rhizoids. Apothecia medium, 

 scattered, sometimes marginal. Disk reddish-brown 

 to dark. Spores typical, 4o/a X 10/u,. 



2. Stictina quercizans. Thallus rather large, lobes 

 rounded and somewhat imbricate, sinuate and crenate, 

 dark-brown above; rhizoids and white cyphella? be- 

 neath. Apothecia rare, medium. Disk dark-brown. 

 Spores typical. 



There are a considerable number of species, but 

 none have marked distinctive characters. The ama- 

 teur will perhaps be satisfied to give the plants col- 

 lected their generic position. In fact, by doing so 

 he will do no small part toward defining the limitations 

 of the two genera. Further study may show that the 

 Stictinas and Stictas devoid of cyphellce do not belong 



here. 



13. Sticta. 



Thallus in all respects similar to that of Stictina. 

 Color less dark and less tinged with blue, owing to 

 the fact that the algaj are briglit-green {Profococ- 

 cus). 



The apothecial and spore-characters are similar. 



