324 39: PARMELIACEAE [154. Parmelia 



5. Parmelia hypotropa Nyl., Syn. Lich. 1:403. 1860. 



P. perforata var. hypotropa Nyl.., Syn. Meth. 1:378,379. 1858. 



Thallus loosely adnate, middle-sized, light greenish gray to white, smooth or 

 slightly wrinkled, sorediate particularly toward the margins, the lobes rather^ broad 

 and not much elongated, somewhat imbricated, with undulate, crenulate, or irregu- 

 lar margins; pale to brownish below with scattered brownish to black rhizoids; 

 apothecia middle-sized to large, 4-12 mm. across, subpedicellate, the disk deeply 

 concave, chestnut-brown, commonly perforate at the center, the exciple entire to 

 crenate ; spores oblong-ellipsoid, 9-1 5 X 6-8 /x. 



On trees and rocks, from South Carolina to Texas, and northward to Massachu- 

 setts and Minnesota, and in California. 



6. Parmelia physodes (L.) Ach., Meth. Lich. 250. 1803. 



Lichen physodes L., Sp. PI. 1144. 1753. P. physodes var. obscurata Ach. P. 

 physodes var. enteromorpha Tuck. P. physodes var. vittata Ach. 



Thallus loosely adnate, usually smooth, greenish gray to ashy, or rarely becom- 

 ing brown or brownish black at the margins and finally throughout, showing open 

 spaces between the upper cortex and the medullary layer, the lobes usually narrow, 

 becoming long and wavy, dichotomously branched and often imbricated, somewhat 

 ascending toward the entire to wavy-crenate and sometimes sorediate margins; 

 brownish black to black below, or brown, or white-sorediate toward the margins, 

 wrinkled and without rhizoids; apothecia rare, middle-sized to large, _ 3-14 mm. 

 across, sessile to subpedicellate, the disk concave, chestnut-brown or lighter, the 

 exciple entire to somewhat irregular; spores subspherical to short-ellipsoid, 4-9 X 

 3.5-6 ju,. 



On trees and rocks, throughout northern United States, and sparingly south- 

 ward (a variable plant). 



7. Parmelia encausta (J. E. Smith) Ach., Meth. Lich. 202. 1803. 

 Lichen encaustus J. E. Smith, Trans. Linn. Soc. 1:83. pi. 4, f. 6. 1791. 

 Thallus middle-sized, loosely adnate, greenish gray to ashy, the crowded, 



wrinkled lobes finally narrowed, round, much branched, interwoven, slightly in- 

 flated, with round margins; brownish black below and without rhizoids; apothecia 

 middle-sized to large, 3-12 mm. across, sessile, the disk flat to slightly convex, 

 chestnut-brown, the exciple crenulate; spores ellipsoid to ovoid-ellipsoid, 7-10 X 

 5-7 fi. 



On trees and rocks, Colorado and the White Mountains. 



8. Parmelia pertusa (Schrank.) Schaer., Lich. Helv. Spic. 10:457. 1839. 

 Lichen pertusus Schrank., Baier. Fl. 2:519. 1789. 



Thallus middle-sized or larger, usually shining, greenish gray to whitish, closely 

 adnate, inflated, perforated by round to oblong holes, bearing scattered, round, 

 white soredia, the lobes crowded, freely branching and often imbricated, their 

 margins scarcely ascending; black below, or brownish toward the margins, wrinkled 

 and without rhizoids; apothecia rare, small to middle-sized, 3-8 mm. across, the 

 disk chestnut-brown, the exciple entire; spores 2-4. ellipsoid, 45-60 X 22-28 /a. 

 (Plate 34.) 



On trees and rarely on rocks. New England, Ohio, Minnesota, and Washington. 



9. Parmelia coralloidea (Meyen & Flot.) Vainio, Act. Soc. Faun. Flor. Fenn. 



7:33,34. 1890. 

 P. perlata var. coralloidea Meyen & Flot., Act. Acad. Caes. Leop. Car. Suppl. 



19:219. 1843. 

 Thallus large, loosely adnate, greenish gray to ashy white, bearing short, slender 

 coralloid branchlets toward the center, the lobes large, not much elongated, ascend- 

 ing toward the entire to wavy-crenate margins; black below with scattered, short, 

 black rhizoids, light or darker brown toward the margins; apothecia middle-sized 

 to large, 5-14 mm. across, perforate at the center, subpedicellate, the disk deeply 



