OF ARTS AND SCIENCES, 219 



Trunks, &c., fertile ; New York, Halsey. — /?, New England. Penn- 

 sylvania, Mulil. The anamorphous development called by Sommerfelt 

 Lecidea Parmeliarum, and referred by Acharius to Endocarpon, occurs 

 not unfrequently in this species, as well as in the next. 



7. P. saxatilis, Ach. Th. subcartilagineous, reticulate-lacunose, 

 glaucous-cinerascent ; black and fibrlllose beneath ; lacinise sinuate- 

 lobed, plane, subretuse ; apoth. dark-chestnut, margin at length cre- 

 nate. Fr. Lichenogr. p. 61. — «; lacinise irregularly imbricate, nar- 

 rower. Ach. Lichenogr. p. 469. — /?. rosceformis, Ach. ; th. orbicular, 

 lobes wider, besprinkled commonly with elongated, marginate soredia ; 

 apoth. smaller, less explanate. Ach. I. c. p. 471. — y. omphalodes., Fr. ; 

 th. smoothish, shining, dark purplish-fuscous, laciniee subtruncate. Fr. 

 Lichenogr. p. 62. Parmelia omphalodes, Ach. Syn. p. 203. 



Rocks and stones, and, somewhat less commonly, on trees and rails, 

 fertile ; New England. New York, Torrey. Pennsylvania, Muhl. 

 Northward to Arctic America, Rich. — y. Arctic America. 



8. P. aleurites, Ach. Th. membranaceous, orbicular, contiguous, 

 rugose-plicate, glaucescent (at length furfuraceous) ; on the under side 

 pale, with fuscous fibres ; lobes discrete at the circumference, plane,, 

 rounded, cut-crenate ; apoih. dark-fuscous, margin at length crenulate. 

 Fr. Lichenogr. p. 62. 



Dead wood, and firs, in mountainous districts, fertile ; and on rocks, 

 sterile. The sterile plant is also common on rails, djc, on the coast. 

 New England. New York, Halsey. Fries refers to this species the 

 P. obsessa, Muhl. Catal., and Ach. Syn. p. 213. 



9. P. IcBvigata, Ach. Th. membranaceous, suborbicular, smooth, 

 glaucescent ; black, and fibrillose on the under side ; lacinife multifid, 

 linear, plane, cut, divaricate (often sorediiferous) ; apoth. chestnut, 

 margin very entire. Ach. Sy7i. p. 212. 



Trunks (very common on beech in mountainous districts), fertile. 



10. P. siniiosa, Ach. Th. membranaceous, suborbicular, smooth, 

 elaucescent ; black, and fibrillose on the under side ; laciniae linear, 

 wider at the circumference, sinuate-pinnatifid, the sinuses wide, circu- 

 lar ; apoth. somewhat plane, fuscous, margin thin, very entire. Ach. 

 Syn. p. 207. 



Trunks and rocks. Nova Scotia, Ach. Fries and Meyer refer this 

 and the last to a single species, but Borrer regards them distinct. 



