154. Parmelia] 39. PARMELIACEAE 333 



sessile, becoming irregular, the disk concave, chestnut-brown and becoming darker, 

 the exciple entire to crenulate or irregular; spores ellipsoid, 8-15 X 7-9 li. 

 On rocks, White Mountains, New Hampshire. 



53. Parmelia prolixa (Ach.) Rohling, Deutschl. El. 3:100. 1813. 



P.olivacea var. prolixa Ach., Meth. Lichi. 214. 1803. P. prolixa var. panniformis 

 Nyl. 



Thallus middle-sized, loosely adnate, olive-brown to brassy-chestnut, becoming 

 wrinkled and bearing coralloid branchlets, the lobes short or becoming elongated, 

 variously branched and often imbricated, sometimes ascending toward the wavy 

 to crenate-cut margins; darker and blackening below, with black rhizoids; apothe- 

 cia small to middle-sized, 3-6 mm. across, the disk concave, brown to brownish 

 black, the exciple entire to subcrenate; spores short-ellipsoid, 8-11 X 5—7 /*. 



On rocks, New England, Illinois, South Dakota, Minnesota, Wyoming, and 

 California. 



54. Parmelia multispora Schneider, Guide Stud. Lich. 154, 155. 1904. 

 P. olivacea var. multispora (Schneider) Merrill. 



Thallus small, possibly reaching middle-size, adnate, olive-brown, lobes wide 

 and short, little branched, the margins round, entire to incised; black below with 

 short, black rhizoids, brown and naked toward the margins; apothecia small to 

 middle-sized, 2-6 mm. across, subsessile, the disk concave to flat, chestnut-brown, 

 the exciple entire to crenulate; spores 16-24 or possibly even 100, ovoid, 8-9 X 

 5-8 [x, or spherical and 6-8 fx in diameter. 



On trees and shrubs, Utah, Idaho, Washington, and California. 



55. Parmelia glabra (Schaer.) Nyl., Flora 55:548. 1872. 



P. olivacea var. corticola f. glabra Schaer., Lich. Helv. Spic. 466. 1840. 



Thallus various shades of brown, often bright and shining, minutely wrinkled, 

 wavy or radiately folded, smooth toward the round lobes, the margins crenate to 

 irregularly cleft, the central lobes of the thallus often ascending or erect; dark 

 brown to black below, with brown margins, and bearing brown to black rhizoids; 

 apothecia small to middle-sized, 0.8-3 mm. across, sessile, the disk strongly con- 

 cave, chestnut-brown, the exciple colored like the thallus, becoming erect and 

 coarsely crenate; hypothecium hyaline; spores ellipsoid, 12-18 X 6-9 /x. 



On rocks and mosses, Nevada, New Mexico, and California (may not be dis- 

 tinct from Parmelia conspurcata). 



56. Parmelia olivacea (L.) Ach., Meth. Lich. 213. 1803. 

 Lichen olivaceus L., Sp. PI. 1143. 1753. P. subolivacea Nyl. 



Thallus small to middle-sized, closely adnate, pale to darker olivaceous, be- 

 coming wrinkled, the lobes moderately wide and not much elongated, often radi- 

 ately branched and sometimes imbricated, the margins entire to wavy-crenate ; 

 olivaceous to more commonly black below, with scattered brown to black rhizoids; 

 apothecia small to middle-sized, 3-7 mm. across, subsessile, the disk concave to 

 flat, chestnut-brown or darker, the exciple entire to crenulate; spores ovoid-ellip- 

 soid, 7-16 X 6-10 fi. 



On trees and wood, throughout northern United States, and southward, espe- 

 cially in the mountains. 



57. Parmelia stygia (L.) Ach., Meth. Lich. 203. 1803. 

 Lichen stygius L., Sp. PI. 1143. 1753. 



Thallus small, loosely adnate, olivaceous brown and shining, finally blackening, 

 the lobes becoming linear, convex, palmately much-branched, the branches round, 

 often twisted and more or less imbricated, the tips usually recurved; of nearly the 

 same color but duller below, and sparingly rhizoid-bearing; apothecia small to 

 middle-sized, 2-8 mm. across, the disk slightly concave, chestnut-brown to black, 

 the exciple subgranular; spores subspherical to short-ellipsoid, 5-12 X 5-7/*. 



On rocks, mostly at high altitudes, from New England westward to Wyoming, 

 and doubtfully to Washington. 



