LICHENS IO3 



LECANORA. 



KEY TO THE SPECIES. 



Thallus lobed, subfoliaceous. 



Thallus having brown radiately chinked warts .gelida. 



Thallus not having brown radiately chinked warts. 



Thallus crustaceous-foliaceous muralis. 



Thallus monophyllous, of many round-lobed, branch-like divisions. 



Disk of apothecia olivaceous or black rubina opaca. 



Disk of apothecia yellowish or red. 



Thallus black beneath, margin of apothecia reflexed.. r#3z'a. 

 Thallus white beneath, margin of apothecia not reflexed. 



straminea. 

 Thallus nearly uniform. 



Apothecia innate, becoming emergent. 



Spores many, very small privigna revertens. 



Spores few, medium size. 



Thallus incrusting mosses occulata. 



Thallus on rocks. 



Thallus subtartareous, areolae smooth cinerea. 



Thallus tartareous, areola? prominent cinerea gibbosa. 



Apothecia superficial. 

 Spores medium size. 



Disk of apothecium black or greenish-black. 

 Disk greenish-black. 



Apothecia small, margin entire, reflexed.. varia intricata. 



Apothecia larger, crenate, not reflexed atrosulphurea. 



Disk of apothecium shining black. 



Margin of apothecium dark gray subfusca coilocarpa. 



Margin of apothecium shining white. 



Apothecia more or less pruinose, margin crenulate. 



pacifica. 



Apothecia not pruinose, margin entire atra. 



Disk of apothecia never black. 

 Apothecia buff-colored. 



Thallus cream-colored, disk of apothecia white pruinose. 



pallida. 



Thallus pale-greenish or yellowish, apothecia not pruinose. 



oaria. 

 Apothecia reddish-brown. 



Thallus smooth, thin, whitish. 



Apothecia very small and crowded hageni. 



