126 LICHENS OF THE STATE OF WASHINGTON 



2. Parmcliopsis diffusa (Web.) Riddle Bryol. 20:75. 1917. 

 Lichen diffusus Web. Spicil. Fl. Goet. 250. 1778. 



Parmelia ambigua var. albescens (Wahl.) Schaer. Enum. Lich. Eur. 

 47. 1850. 



Thallus whitish to cinereous (R) or grayish olive (R), suborbicular, 

 closely adnate, smooth to even shiny near the edges, lobes linear, radiate, 

 much branched dichotomously, margins crenate, tips rounded, rimulose and 

 broken towards the center, with raised balls of white sometimes grayish 

 soredia, crowded towards the center, never isidiose ; below brownish, black 

 with scattered black rhizoids. Apothecia rare, 2-6 mm. in diameter; disk 

 pale brown to chestnut brown, concave to convex ; thalline margin con- 

 colorous with the thallus, crenulate ; asci 8-spored ; spores hyaline, straight 

 or curved, oblong, nonseptate, 7.0-10.0 x 2.0-3.3 fi. 



On trees and decaying wood : Pierce Co. : Silver Springs, 2670 ft., 1931, 

 721; White River Camp, 3900 ft., 1940, 3103; Mt. Rainier, Paradise Park, 

 5550 ft., 1928, 1921; Berkeley Park, 6000 ft., 1940, 3020. Pierce-Yakima 

 Co.: Chinook Pass, 5440 ft., 1559. Kittitas Co.: Easton, 2168 ft., 1931, 

 926. Olympic Mountains, Camp Elkhorn, 2000 ft., 1907, Frye 73 (F), 

 this specimen determined as Parmelia hyperopia by G. K. Merrill. Ferry 

 Co.: Republic, 1912, Foster 2292 (F), this specimen determined as 

 Parmelia diffusa var. albescens by G. K. Merrill. 



Riddle (1917) has been the basis for the treatment of this genus. 



54. Parmelia Ach. Meth. 153. 1803. 



Thallus foliose, rarely subfruticose, variously lobed, smooth, sorediate, 

 or isidiose, sometimes ciliate on the margins, well-developed upper and 

 lower plectenchymatous cortices, also medullary and algal layers, lower 

 surface either lighter or darker than the upper, with or without rhizoids. 

 Apothecia scattered on the upper surface, never marginal, shield-shaped 

 (scutellate), sessile or subpedicellate, thalline margin prominent; hypo- 

 thecium hyaline; paraphyses usually branched, septate, embedded in a 

 jell and enlarged at the tips ; asci commonly 8-spored, rarely more numer- 

 ous; spores hyaline, nonseptate. 



A. Subfruticose, black or very dark brown. 



B. Lobes filamentous. 12. P. pubescens 



B. Lobes narrowly membranaceous, never more than 1 mm. wide. 



13. P. stygia 

 A. Foliose. 



C. Never bearing rhizoids below. 



D. Thallus perforated with occasional small holes 7. P. pertusa 



D. Thallus never perforated with small holes. 



E. Cribrose below 3. P. lophyrea 



E. Not cribrose below. 



F. Lobes much inflated, usually elongated, black spermagonia 

 often abundant. 



