402 PROCEEDINGS OF THE AMERICAN ACADEMY 



Lecidea sorediata, mainly by the lighter color and thinner texture of 

 its smoother lobes, and their smoothish under-side ; and Mr. Wright's 

 Cuban collections appear fully to confirm Dr. Nylander's opinion (Lich. 

 Exot. in Ann. Sci. 4, 11, p. 239), that neither of these differences, nor 

 that of size, which extends even to the spores, is sufficient to separate 

 specifically the tropical form from the more northern one. The present, 

 so far as my specimens go, appears to be a smaller and less imbricated 

 Lichen than P. Meissneri, from which it also differs in its white medul- 

 lary layer, and especially in its apothecia, which are exactly those of 

 the genus, as described by Fries, and, more at large, by Eschweiler. 

 There is also in P. Cocoes a tendency to sorediate efflorescence, which 

 becomes marked and characteristical in the northern Lichen, which, I 

 cannot but think, deserves still a separate, if a subordinate place. 



Var. /3. SOREDIATA : thallo cartilagineo glauco-cinerascente intus 

 fusco-sulphureo (pallescente), laciuiis rugoso-plicatis ; sorediis rotun- 

 datis csesiis marginalibus exasperatis subtus subspongioso-fibrillosis ; 

 apotheciis ca^sio-pruinosis (nudis). Lecidea sorediata, Ach. Syn. p. 54. 

 Pyxiiie, Fr. PI. Homon. p. 267. Lecidea (§ Pyxine), Eschw. Bras. 

 1. c. p. 245. Parmelia (§ Pyxine), Tuckerm. Synops. Lich. N. E. 

 p. 35, & Lich. Exs. n. 19. Lecidea albo-virens, Eschw. Bras. 1. c. 

 p. 256. On trees and rocks, Pennsylvania, Muhleixberg (Ach. Syn. 

 1. c. 1814). New England to Virginia, not rare, especially on moun- 

 tains. Westward to the Rocky Mountains, Herb. Hook. North Car- 

 olina, Rev. Dr. Curtis. South Carolina and Georgia, Mr. Ravenel. 

 Alabama, Mr. Peters. Mississippi, Dr. Veitch. Louisiana, Dr. Hale. 

 Texas, where occur also small forms like a, 3fr. Wright. The same 

 unwearied botanist has collected the Lichen also in Cuba, and in Japan. 

 And I am indebted to Dr. Hooker for an infertile, but otherwise 

 undistinguishable specimen from the Himalaya, and to Dr. Van den 

 Bosch for satisfactory ones from Java. It was upon this Lichen, first 

 observed by Muhlenberg, that Fries constituted his genus. The plant 

 differs from the earlier P. Cocoes (Sw.), Nyl., in being every way 

 larger ; in its darker, finally ashy color ; its regular soredia ; and 

 densely spongy-fibrillose under-side : but approaches P. Meissnei-i (to 

 which P. sorediata, Montag., Cuba, 1, c, should perhaps be referred, 

 in part at least) in its dark-yellow (sometimes fuscous, and often pal- 

 lescent) medullary layer ; which is observable (as indicated by Esch- 

 weiler in his Lecidea albo-virens), if nowhere else, immediately beneath 



