80 



LICHENS. 



Apothecium, an open fruit patch. 



Cntstaceous, forming a hard, dry incrustation, closely adhering to 

 the surface on which it grows. 



Gonidia, large, green, gray-green, or yellow cells, single or in 

 thread-like clusters contained in the net work of fine, thread-like, 

 colorless cells. 



ffypothattus, a membrane or substratum consisting of thread-like 

 cells, but differing in appearance from the rest of the plant. 



Perithecium, an envelope or involucrura surrounding a narrow- 

 mouthed fruit patch. 



Stroma, a thick mass of thread-like cells. 



177. Apothecium circular, spread out flat, with a margin of the same 

 structure as the thallus itself, that is, colored by green or grayish 

 gonidia. Parmeliacei. 181 



Fruit patches usually with a border or involucrura unlike the rest 

 of the thallus, or else without a border. 



Perithecium globular, pierced by a small opening at the apex. 



Verrucariei. 179 

 Fruit patch in an open apothecium. 



Apothecium rounded, spread out flat, plate-form. 



Lecidiacei. 180 

 Apothecium bowl-form or globular, mostly borne on a short stalk, 



its disc closely covered with naked spores. Caliciacei. 178 

 Apothecia of various forms, but usually elongated and furrow-like. 



Thallus crustaceous, or like a dry incrustation. Graphidiacei. 



Apothecia long, narrow, and furrow-like. OPEQRAPIIEI. 

 Apothecia many, collected in a stroraa, or swelled out mass. 



GLYPHIDIEI. 



Apothecia roundish, flat, rarely elongated. LKCANACTIDEI. 

 Apothecia partially running together, of various forms, with no 

 border. AKTHONIKI. 



178. Thallus erect, branching, bushy. 

 Thallus crust like. CALICIEI. 



