32 GUIDE TO CRYPTOGAMS. 



Stereocaulon. Apothecia brown. Podetia solid, covered 

 more or less with granules. 



Cladonia. Apothecia brown, red or yellow. Podetia hollow. 

 9 c. Thallus crustaceous. Apothecia borne on stalks. 



Bseomyces. Apothecia globose from the first (in our species 

 pink or flesh color). 



9d. Thallus crustaceous. Apothecia sessile, patello?form 

 or cephaloid, the exciple coal-black, 



Lecidea. Spores colorless. 

 Buellia. Spores brown. 

 2 c. Apothecium usually elongated or lirellaform, margined 



by a proper exciple and often also by a thalline 



one; hymenium concave. 



Opegrapha. Apothecia with only a proper exciple, which is 

 usually black throughout. 



Graphis. Apothecia w T ith a proper exciple which is usually 

 white below, and a more or less prominent thalline exciple. 



2 d. Apothecia globose or crateriform ; disk consisting of 

 a powdery mass of naked spores (the asci having 

 early broken up). 

 Sphaerophorus. Thallus vertical, fruticulose. Apothecia 

 globose, formed by the swollen tips of the branches. 



Acolium. Thallus crustaceous. Apothecia crateriform or 

 urn-shaped, sessile. 



1 b. Apothecia icith the hymenium enclosed in a perithecium 

 which opens only by a pore at the summit. (See 

 Pertusaria.) 

 10 a. Thallus foliaceous, sometimes squamulose. 

 Endocarpon. Apothecium indicated on the surface of the 

 thallus only by a minute pore. 



10 b. Thallus crustaceous, often very obscure. 



11a. Apothecia collected many together in a convex stroma. 



Trypethelium. On bark of trees. 



lib. Apothecia solitary. 

 Verrucaria. Apothecia innate, perithecium black. On rocks. 

 Pyrenula. Apothecia somewhat prominent. On bark of 

 trees. Otherwise as in Verrucaria. 



