GENERA AND SPECIES. 195 



The apothecia resemble those of Peltigera ; the disk 

 is brown to dark-brown. The spores are elliptical, 

 two-celled and brown in color. 



The Solorinas are northern in their range, occurring 

 among moss, upon rock and soil. 



1. Solorina crocea. Thallus rather small, not dis- 

 tinctly branching, closely adnate to substratum ; brown 

 above, orange-red beneath, with darker veins. Apo- 

 thecia medium to large. Disk reddish-brown. Spores 

 typical of genus, 50/x, X 20/a. 



2. Solorina saccata. Thallus thinner than in S. 

 croceay paler. Apothecia medium, in depressions of 

 the thallus. Spores typical, 50/tx X 20/x. 



11. Nephromium. 



The thallus of Nephromium has a distinct, well- 

 developed Ibwer cortical layer, from the lower surface 

 of which extend long rhizoids. In other respects the 

 thallus resembles that of the Peltigeras. (The algae 

 are blue-green and occur in colonies as in Peltigera.') 



The apothecia are more or less oval or kidney-shaped 

 and are marginal upon the lower surface of upturned 

 lobes, a character not found in any other lichen-group. 

 The disk is reddish-brown. The spores vary from 

 nearly acicular to oval, usually four-celled and brown. 



Some species have bright-green algte (Protococcus), 

 and should be classed with another genus {Nephroma). 



The species are northern in their range, and occur 

 upon rock and tree-trunks in shaded places. 



i. Nephromium*l(Evigatum. Tliallus medium, lobes 

 rather small, rounded, undulate, brown above; paler 



