270 FLORA OF MOUNT DESERT. 



B. petraea (Plot.), Tuck. 



On rocks. (Eckfeldt) ; Seal Harbor (Wilson). 

 B. geographica (L.), Tuck. 



On rocks. Seal Harbor (Wilson). 



TRIBE III. GRAPHIDACEI. 

 OPEGRAPHEI. 



OPEGRAPHA, Humb.* 



* 0. demissa, Tuck. 



On smooth bark. (Eckfeldt.) 

 *0. viridis (Pers.), Nyl. 



Thallus light ochrous yellow, very thin, mostly scurfy or 

 slightly tartareous, rimose, constricted. Apothecia short, innate, 

 from round to elongate and linear, mostly curved and undivided 

 with the margin incurved. Spores in thekes 8, hyaline, fusi- 

 form to acicular, 11 to 13-locular, '^1'^ mic. " Mt. Desert " 

 (Eckfeldt). 



XYLOGRAPHA, Fries. 



* X. disseminata, Willey. 



On dead wood. " Mt. Desert " (Willey). 

 X. Opegraphella, Nyl. 



On old fence rails. Seal Harbor (Wilson). 



GRAPHIS, Ach. 

 G. scripta (L.), Ach. 



Thallus grayish white, very thin, membranaceous, tartareous 

 even, and frequently rugose. Apothecia slender,, immersed, 

 waving, margins narrow and elevated. Spores hyaline, elon- 

 gated, and cylindrical, 8-10-septate, ^ ~ ^ mic. Seal Harbor 

 (Wilson, Eckfeldt). 



* For description of genus, see Tuck., Syn. N. A. Lichens, part I, 11. 



