62 PARMELIA. 



Middle States, Muhlenberg. Southern States to Louisiana, 

 Curtis, Hale, etc. It occurs also in tropical America (P,. para- 

 sitica, Fee, e Nyl.). 



* * Thattus olivaceous -brown. 



13. P. olivacea (L.) Ach.; tballus inembranaceous, plicate- 

 radious, becoming rngulose, and now isidiophorous, from pale- at 

 length dark-olivaceous, and brown ; beneath black, with more or 

 less frequent blackening fibrils ; lobes flattish, rounded, crenate; 

 apothecia middling- sized; disk chestnut, with a wrinkled or 



crenulate margin. Spores short-ellipsoid, ~ mic. Ach. L. U. 



p. 462. Fr. L. E. p. 66. Nyl. Syn. I, p. 395. 



* aspidota, Ach. ; thallus, and apothecia externally, thickly 

 beset with minute warts of the same colour. Spores more 



rounded, and smaller. Ach. I.e. Th. Fr. Lich. Scand.p. 122. 



P. (sub-sp.) exasperata, Nyl. 1. c. 



b. prolixa, Ach. ; thallus narrowed, many-cleft. Spores 

 smaller. Ach. I. c. Nyl. I. c. 



* panniformis, Nyl.; lobes (except those of the periphery) 

 divided into short, irregularly cleft, densely crowded and imbri- 

 cate ones, now passing into finger- shaped branchlets. Nyl. I.e. 



Exs. Anz. Lang. n. 428. 



c. sorediata (Ach.) Nyl.; thallus narrowed as in b, the more 

 discrete, many-cleft, lacunulose lobes beset with pulvinate, white 



soredia. Nyl. Lich. Scand. p. 102. P. dmdritica, Fr. L. E. 



p. 68, fide ipsius. P. (sub-sp.) sorediata, Th. Fr. Lich. Scand. 

 p. 123. 



Trees and rocks, a, on trees ; northern, and middle States, 

 Muhlenberg Catal. 1818. Arctic America, Richardson. Mount- 

 ains of North Carolina, Havenel. New Mexico, Wright. Cali- 

 fornia, Bolander. British Columbia, Macoun. b, on rocks; 



Mountains of New England, C. C. Frost, etc. California, Bolander. 



c, on rocks; New England, Tuckerman. California, Bolander. 



British Columbia, Macoun. Spores (in the few specimens at 

 hand) of a * clearly smaller ; as they are found to be in Europe. 

 But a occurs, in the otherwise well-characterized New Mexico 

 specimens, with similarly reduced spores. Spores of b, in the New 

 England lichen, -^ mic.; but larger, and approaching at length 

 very closely, in dimensions, to a, in the Californian. 



