66 HERRE 



Apothecia numerous, linear, very irregularly shaped, branching, 

 stellate, curved, or straight; innate, with sunken disk, or becoming 

 somewhat elevated; brown to black; epithecium granulose, blackish; 

 thecium colorless, the asci short, pear-shaped or almost oval; blue 

 with I, then slowly turning to vinous red, only the asci stained 



yellowish ; spores ovoid-oblong, 4-locular, -^ ^ and ^ fJ- 



Abundant on trees throughout; an exceedingly variable plant, 

 found all over the world. 



I have referred to this species a large series of Arthonias which 

 vary in several particulars, but which agree pretty well in spore 

 characters. 



GRAPHIDACE^. 



Thallus uniform crustaceous, cortex absent or poorly developed, 

 with Palmella or Trentepohlia alga, in our species only the latter. 

 Apothecia usually linear, rarely circular or spot-Uke, sohtary, or 

 aggregate, but not forming stroma; simple or branched, with a well 

 developed proper margin, frequently with a thalhne margin; disk 

 usually narrow and fissure-hke; paraphyses simple and unbranched 

 or branched and twining; rarely gelatinizing. Spermatia exobasi- 

 dial. 



KEY TO GENERA. 



Paraphyses branched, twining XIII. Opegrapha 



Paraphyses simple, not twining XIV. Phceographis 



XIII. Opegrapha. 



Opegrapha Humboldt, Fl. Frib. 57. 1793. 



Alga Trentepohlia. Apothecia innate, appressed or sessile, usu- 

 ally more or less elongate, with a black proper margin; hypothecium 

 clear or dark; spores 8, oval, elhpsoid, or spindle-shaped, straight or 

 bowed, colorless, 2-18-locular. 



Numerous species, on rocks, wood, and bark, distributed all over 

 the world. 



KEY TO THE SPECIES. 



Spores 6-locular 3. varia 



Spores 4-locular 



On maritime rocks i . saxicola 



On bark of trees 2. prosiliens 



