326 39. PARMELIACEAE [ 154. Parmelia 



15. Parmelia cetrata Ach., Syn. Meth. Lich. 198. 1814. 



Thallus large, adnate, light or darker greenish gray, sometimes becoming 

 wrinkled toward the center, the lobes short and wide or elongated and branched, 

 wavy-incised, usually ascending toward the more or less sorediate or rarely ciliate 

 margins; black below with rhizoids of the same color, usually brown toward the 

 margins; apothecia middle-sized to large, 4-15 mm. across, subpedicellate, the disk 

 chestnut-brown, more or less deeply concave, commonly perforate at the center, 

 the exciple entire to crenate; spores oblong-ellipsoid, 10^16 X 6-8 \x. 



On trees, old wood, and rocks, widely distributed throughout the United States, 

 but usually sterile. 



16. Parmelia Finkii Zahlbr.; Hedrick, Mycologia 26:162. 1934. 



Thallus small, adnate, greenish gray to ashy, bearing small coralloid branchlets 

 of the same colors, the lobes becoming moderately elongated and laterally 

 branched, sometimes imbricated, the tips entire or rarely crenate, often narrowed; 

 black and roughened below, with few and scattered obscure rhizoids; apothecia 

 small, 2-3 mm. across, the disk concave, chestnut-brown, the exciple crenate to 

 obscurely coralloid-lobed; spores oblong-ellipsoid, 8-11 X 4.5-6 fx. 



On bark and on mosses over the bark, Wayne County, Missouri. 



17. Parmelia caroliniana Nyl., Flora 68:614. 1885. 



Thallus middle-sized, grayish white, more or less roughened and reticulated, 

 becoming sparingly fibrillose and bearing coralloid branchlets, the lobes somewhat 

 narrow, with wavy-incised margins; brownish black below, with scattered rhizoids; 

 apothecia small, 2-3 mm. across, the disk concave, brick-red to chestnut-brown, 

 the exciple entire, bearing obscure coralloid branchlets; spores ellipsoid, 12-14 X 

 6-7 ix. 



On trees, South Carolina. 



18. Parmelia saxatilis (L.) Ach., Meth. Lich. 204,205. 1803. 



Lichen saxatilis L., Sp. PI. 1142. 1753. P. saxatilis var. jurftiracea Schaer. 

 P. saxatilis var. laevis Nyl. P. saxatilis f. pannijormis (Ach.) Schaer. 



Thallus middle-sized, rather closely adnate, smooth to obscurely wrinkled, 

 greenish gray to ashy or rarely brown, often bearing coralloid granules or branch- 

 lets, the lobes commonly long, narrow, and subdichotomously branched, with wavy 

 margins; black below, or brown toward the margins, covered with black rhizoids; 

 apothecia rare, middle-sized to large, 4-12 mm. across, subsessile, the disk concave 

 or deeply concave, chestnut-brown, the exciple irregular or crenulate; spores ellip- 

 soid, 10-20 X 7-12 jx. 



On trees, wood, and rocks, northern United States, but rare southward (the 

 plants on rocks are usually smaller). 



19. Parmelia frondifera Merrill, Bryologist 11:91. 1908. 



Thallus small to middle-sized or rarely larger, round to expanded, more or less 

 closely adnate, greenish gray to more commonly brownish, irregularly lobed, the 

 lobes divided and often much imbricated, more or less covered with minute, finely 

 divided lobules; white within; black below or brownish toward the margins, bear- 

 ing short black or brownish rhizoids; apothecia rather large, short-pedicellate, 

 the disk deeply concave, light chestnut-brown, the exciple radiately rugose and 

 sometimes fissured; spores oblong-ellipsoid, 10 X 5-7 fx. 



On old wood and trees, New York, North Carolina, and Florida (herbarium 

 specimen sterile, the apothecial characters taken from Merrill). 



20. Parmelia lophyrea Ach., Meth. Lich. 198. 1803. 

 P. cribellata Tayl. 



Thallus small, loosely adnate, greenish gray to ashy, rarely sorediate, the lobes 

 narrow, not much elongated, more or less branched, fiat, sometimes lacunulose, 



