154. Parmelia] 39. PARMELIACEAE 331 



to middle-sized, 3-10 mm. across, the disk deeply concave, chestnut-brown, the 

 exciple entire to crenate; spores ellipsoid, 18-24 X 7-13 /x. 



On trees, from Virginia to Florida and westward to Texas (possibly a color 

 form of Parmelia crinita Ach.). 



43. Parmelia aurulenta Tuck., Am. Journ. Sci. II. 25:424. 1858. 



Thallus small to middle-sized, adnate, greenish to yellowish gray, wrinkled, 

 sprinkled over more or less densely with whitish or yellowish, often confluent 

 soredia, sulphur-yellow internally, the lobes short and wide, somewhat branched 

 with round, entire to irregular margins; brownish black to black below with 

 blackening rhizoids ; apothecia small to middle-sized, 5-10 mm. across, subsessile, 

 the disk concave, chestnut-brown, the exciple entire to wavy-crenate ; spores ellip- 

 soid, 10-16 X 4-7 fi. 



On trees and rocks, from the White Mountains westward to Minnesota, and 



southward to Alabama and Louisiana. 



44. Parmelia soredica Nyl., Flora 68:605. 1885. 



Thallus large, adnate, greenish gray to yellowish green, bearing white soredia 

 and breaking away centrally, the lobes rather wide, more or less branched, the 

 peripheral ascending lobes wavy-crenate, the other lobes ascending and confluently 

 white-sorediate ; black below, often brown and rarely bearing black rhizoids toward 

 the margins; apothecia middle-sized, 4-10 mm. across, sessile, the disk concave, 

 chestnut-brown, the exciple entire to lobulate, usually sorediate; spores short-ellip- 

 soid, 11-14X6-8 fi. 



On trees, old wood, and rocks, Santa Cruz Peninsula, California. 



45. Parmelia scortella Nyl., Flora 68:615. 1885. 



Thallus small to middle-sized or rarely larger, thin, closely adnate, greenish to 

 yellowish gray, the lobes short to somewhat elongated, subdichotomously branched, 

 more or less covered by minute coralloid branchlets; black below, with many 

 black rhizoids; apothecia small, 2-6 mm. across, subsessile, the disk slightly con- 

 cave to flat or slightly convex, chestnut-brown, the exciple entire to crenate and 

 bearing minute coralloid branchlets; spores short-ellipsoid, 8-10X4-5/*. 



On trees, Texas (doubtfully admitted). 



46. Parmelia conspersa (Ehrh.) Ach., Meth. Lich. 205. 1803. 



Lichen conspersus Ehrh.; Ach., Lich. Suec. 118. 1798. P. conspersa v&r.steno- 

 phylla Ach. P. subconspersa Nyl. P. conspersa var. imbricata Mass. P. con- 

 spersa f. isidiata Anzi. 



Thallus closely adnate, middle-sized or larger, straw-colored, varying toward 

 greenish or yellowish, smooth or somewhat wrinkled, often sorediate or bearing 

 coralloid branchlets toward the center, the lobes long and rather narrow, crowded 

 and often imbricated, sometimes much branched, the margins wavy to crenate, 

 the imbricated central lobes often forming a continuous crust; black below with 

 brown margins, dark rhizoids usually present; apothecia subsessile, small to middle- 

 sized, 3-12 mm. across, the disk concave, chestnut-brown, the exciple subentire to 

 crenulate; spores ellipsoid, 8-12 X 4.5-7 fi. 



On rocks and rarely on wood, throughout northern United States, and south- 

 ward in the mountains. 



47. Parmelia laevigata (J. E. Smith) Ach., Syn. Meth. Lich. 212. 1814. 

 Lichen laevigatas J. E. Smith, in Sowerby, Engl. Bot. 24: pi. 1852. 1808. 



P. laevigata var. sinuosa (Ach.) Nyl. 



Thallus thin, smooth, middle-sized, loosely adnate, pale yellowish to light 

 greenish gray, sometimes sorediate, the lobes narrow, often imbricated, with crenate 

 margins; black below with middle-sized black rhizoids; apothecia small to middle- 

 sized, 3-6 mm. across, the disk concave, chestnut-brown, the exciple entire to 

 serrate; spores ellipsoid, 12-22 X 6-10 ft. 



On trees and rocks, from Florida to Louisiana, and doubtfully northward to 

 New England, and in Illinois. 



