320 



39. PARMELIACEAE [154. Parmelia 



2. Parmeliopsis aleurites (Ach.) NyL, Not. Sallsk. Faun. Flor. Fenn. 8:121. 



1866. 



Lichen aleurites Ach., Lich. Prod. 117. 1798. Cetraria aleurites (Ach.) T. Fries. 

 P. pallescens (Neck.) Zahlbr. 



Thallus small, round, adnate, greenish gray to ashy or brownish, smooth 

 toward the margin, elsewhere wrinkled and densely covered with whitish to 

 brownish coralloid granules, the lobes short, narrow, with round to crenate mar- 

 gins; whitish and wrinkled below, with scattered brownish rhizoids; apothecia 

 small, 1.5-3 mm. across, or reaching 5 mm., sessile, the disk concave, chestnut- 

 brown, the exciple colored like the thallus, crenulate to lobulate; spores broadly 

 ellipsoid, 4.5-9 X 3.5-5 (i. (Plate 33.) 



On trees and old wood, Connecticut, Pennsylvania, and Michigan. 



var. diffusa (Ach.) Riddle, Bryologist 20:74. 1917. 

 Parmelia aleurites var. diffusa Ach., Lich. Univ. 485. 1810. 

 Thallus irregularly and somewhat imbricately lobed, the coralloid granules 

 smaller, fewer, and scattered. 



On trees and old wood, from New England to Georgia. 



3. Parmeliopsis ambigua (Wulf.) NyL, Syn. Lich. 2:54. pi. 9, f. 4. 1860. 

 Lichen ambiguus Wulf., in Jacq., Coll. Bot. 4:239. pi. 4, f. 2. 1790. Parmelia 



ambigua (Wulf.) Ach. Parmelia diffusa (Schrad.) T. Fries. 



Thallus small to middle-sized, round, adnate, smooth toward the circumference 

 and chinky and broken toward the center, straw-colored to ashy white or yellow, 

 more or less densely covered with yellowish or sulphur-colored soredia or soralia, 

 the lobes elongated, dichotomously much-branched, often imbricated, the margins 

 wavy to incised-crenate; chestnut-brown below, varying toward blackish, with 

 scattered black rhizoids; apothecia small to middle-sized, 1-5 mm. across, sessile, 

 the disk concave to convex, chestnut-brown to darker, the exciple colored like 

 the thallus, becoming crenulate; spores oblong-ovoid, commonly curved, 8-13 X 

 2—3.5 fi. 



On trees, old wood, and rocks, from New England to South Carolina, and west- 

 ward to Wyoming and New Mexico. 



var. Halei (Tuck.) Zahlbr., Cat. Lich. Univ. 6:13. 1929. 



Parmelia ambigua var. Halei Tuck., Syn. N.A. Lich. 1:66. 1882. 



Apothecia somewhat larger than in the species, with wax-colored disk and a 

 constantly powdery-sorediate exciple. 



On coniferous trees, Massachusetts, New Jersey, Virginia, South Carolina, and 

 Louisiana. 



4. Parmeliopsis diffusa (Weber) Riddle, Bryologist 20:75. 1917. 



Lichen diffusus Weber, Sp. Fl. Goett. 250. 1778. Parmelia ambigua var. albes- 

 cens (Wahl.) Schaer. Parmelia hyperopia Ach. 



Thallus round, small to middle-sized, adnate, whitish to ashy or ashy brown, 

 smooth and shining toward the circumference to chinky toward the center, with 

 more or less elevated, whitish to dirty-ashy, scattered or clustered soredia, in the 

 latter condition forming soralia, the lobes more or less regularly radiate, dichot- 

 omously much-branched, the margins crenate; brownish black below, with scat- 

 tered, black rhizoids; apothecia small to middle-sized, 2-6 mm. across, sessile, the 

 disk fiat to slightly convex, chestnut-brown to darker, the exciple colored like the 

 thallus, crenulate; spores oblong-ovoid, commonly curved, 8-15 X 2-3.5 fi. 



On trees, old wood, and rocks, Maine, New Hampshire, New York, and Wash- 

 ington. 



154. Parmelia Ach., Meth. Lich. 153. pi. 4, f. 3-6. 1803. 



Thallus foliose or rarely somewhat fruticose, more or less lobed, smooth or 

 more or less covered by soredia or coralloid branchlets, sometimes ciliate along the 

 margins, differentiated into well-developed, plectenchymatous upper and lower cor- 



