72 PHYSCIA. 



fringed with small lobules; apothecia as in a, or the border 



fringed finally like the lobes. Spores bilocular, ^ mic. Obs. 



Lich. 1, 1. c.p. 389. P. detonsa, Fr. S. 0. V. p. 284. Tuckerm. 

 Syn. N. E. p. 32; Lich. exs. n. 18. Psoroma palmulata, Michx., 

 .fide Mull. 



Rocks, and trees. b, North America, Fries I. c. 1825. Com- 

 mon from New England to Virginia, Tucker man ; and through- 

 out the southern Atlantic and Gulf States (Ravenel, etc.); Ohio, 

 Lea. And the same lichen was found in Japan by Mr. Wright ; 



Tbut it is not known from our Pacific coast. Lobes more or less 



elongated, and at length exceedingly narrowed in the tree-form; 

 ;and our lichen is generally noticeable for its paleness, and fre- 

 quent luxuriance of lobation. It yet also occurs quite undis- 

 tinguishable from the European. Spores of the foreign plant 

 agreeing in every respect with those of ours. This is probably 

 the P. aquila of Muhl. Gated., whether or not determined by 

 Acharius. 



* * Pliyscia proper. Cortical layer of the upper side pa- 

 renchymatous. 



5. P. pulverulenta (Schreb.) Nyl. ; thallus cartilagineous, 

 stellate, from greenish becoming brown, more or less pruinose ; 

 beneath black-fibrillose ; lobes multifid, crenate, the tips rounded ; 

 apothecia middling-sized, sessile, the flat, blackish-brown, sub- 

 pruinose disk bordered by a thick, at length lobulate, or leafy 



margin. Spores bilocular, |^ mic. Parmelia, Fr. L. E.p. 79. 



Nyl. Syn. 1, p. 419. 



a. lobes narrower than in b, and the margins not elevated 

 nor powdery; the thallus passing often at the centre into 

 crowded, small, convex lobules. 



b. leucoleiptes, Tuckerm. ; lobes flat, interruptedly elevated 



and powdery at the margins, beneath black. Syn. N. Eng. p. 



32. Lich. Amer. exs. n. 107. 



On trunks, and rocks ; and on the earth, a, Pennsylvania, 

 Muhlenberg Catal. 1818, and common northward ; and westward 

 to California, Bolander-, the earth-form (/. muscigena, Auct.) 

 having been observed in Newfoundland, Despreaux (Herb. 



Spreng.), and Arctic America, Eichardson (Herb. Hook.). b, 



Pennsylvania, Muhlenberg, and northward to New England; 

 southward it is found in Virginia; and also in New Mexico, 

 Fendler-, and California, Bolander. 



