154. Parmelia] 39. PARMELIACEAE 329 



Thallus small to middle-sized, adnate, greenish gray, usually more or less 

 wrinkled, sulphur-yellow within, the lobes short or more or less elongated and 

 branched, the margins entire to crenate; black below and bearing black rhizoids; 

 apothecia middle-sized, 3-10 mm. across, subsessile, the disk more or less concave, 

 chestnut-brown, the exciple entire to crenate; spores short-ellipsoid, 6-10 X 4-6 /a. 



On trees, Illinois. 



32. Parmelia colpodes (Ach.) Nyl., Syn. Meth. Lich. 404. 1858. 



Lichen colpodes Ach., Lich. Suec. 124. 1798. P. cristulata Ach. Imbricaria con- 

 vexiuscida Michx. Anzia colpodes (Ach.) Stizenb. 



Thallus thin and rather flat, grayish green, varying toward whitish or brownish, 

 the lobes deeply much-branched, radiately clustered toward the margins; covered 

 below by a dense, spongy, dark brown to black nap and scattered coarse rhizoids; 

 apothecia small to middle-sized, 3-8 mm. across, sessile to subpedicellate, the disk 

 concave, chestnut-brown and becoming darker, the exciple entire; spores many, 

 oblong or club-shaped, often curved, 3-6 X 1.2-2 fi. 



On trees, throughout eastern United States, west to Louisiana and Nebraska. 



33. Parmelia sphaerosporella Mull. Arg., Flora 74:378. 1891. 



Thallus small to middle-sized, adnate, greenish yellow, roughened and folded, 

 the lobes wide, closely placed toward the center, but spreading and branched 

 toward the obtuse, crenate margins; pale below and bearing pale rhizoids; apo- 

 thecia small to middle-sized, 3-6 mm. across, the disk deeply concave to flat, flesh- 

 colored to brown, the exciple entire, narrow, and externally rough; spores spherical, 

 5-7 fx. in diameter. 



On trees, Montana, Oregon, and California. 



34. Parmelia leucochlora Tuck., Syn. N. A. Lich. 1:64. 1882. 

 P.conspersa wax. leucochlora Tuck., in Nyl., Syn. Meth. Lich. 1:392. 1858. 

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



straw-colored, the lobes flat, rather narrow, becoming elongated and branched, 

 often imbricated, the margins wavy to crenate; light- to chestnut-brown below 

 with darker rhizoids; apothecia small, 2-5 mm. across, sessile, the disk concave, 

 chestnut-brown, the exciple entire to subentire; spores ovoid-ellipsoid, 7-10 X 5-7 fi. 

 Commonly on bald cypresses, from South Carolina to Florida, and westward 

 to Missouri and Arkansas. 



35. Parmelia centrifuga (L.) Ach., Meth. Lich. 206. 1803. 

 Lichen centrifugus L., Sp. PI. 1142. 1753. 



Thallus small, adnate, yellowish or greenish straw-colored, the central crust of 

 convex, imbricated, wrinkled, frequently disappearing lobes, the marginal lobes 

 more elongated, with sinuous, crenate, or incised margins; white below, with 

 darker rhizoids; apothecia small to middle-sized, 3-8 mm. across, sessile, the disk 

 concave, chestnut-brown, the exciple subcrenulate ; spores ellipsoid, 7-10X4.5- 

 5.5 /a. 



On rocks, Maine, New Hampshire, Massachusetts, and Minnesota. 



36. Parmelia incurva (Pers.) E. Fries, Sched. Crit. Lich. Exsicc. Suec. fasc. 9. 



31. 1826. 



Lichen incurvus Pers., Ann. Bot. Usteri 1:24. 1794. P.recurva Ach. 



Thallus middle-sized, loosely adnate, varying from greenish to yellowish straw- 

 colored, bearing raised whitish to sulphur-colored soredia, the lobes narrow, 

 strongly convex, much branched, the branches crowded and often imbricated, the 

 margins somewhat incurved; pale below with blackening rhizoids; apothecia small 

 to middle-sized, 3-7 mm. across, the disk concave to flat, chestnut- to darker 

 brown, the exciple subentire; spores ellipsoid, 7-13 X 5-6 /x. 



On granitic rocks, New Hampshire and Maine. 



