62 LICHENES OF THE NORTHERN STATES 



ulate-verrucose and somewhat plicate, glaucescent ; hypoth. pale ; 

 apoth. elevated-subpedicellate on a thalline stratum, which constitutes 

 a thick, subcrenulate, at length evanescent spurious margin ; disk 

 plane, delicately pruinate, at length convex, and excluding its thin, 

 elevated, proper margin, from pale flesh-colored becoming blackish- 

 fuscous. 



Trunks in the mountainous districts of Northern New England, 

 common. Apothecia at first closed, and either sessile (when some 

 states resemble Parmelia carneo-lutea, Turn.) or elevated on a protu- 

 berant thalline stratum, at length lacerate-dehiscent and becoming plane, 

 with a thick, crenulate thalline margin, which disappears, leaving the 

 marginate disk. It has often all the aspect of a Parmelia, not a little 

 resembling P. rubra. Is the structure of the apothecia in the last-men- 

 tioned species, and in P. carneo-lutea, wholly diverse from the structure 

 above described of the present .' 



20. B. russula, Tuckerm. Cr. subcartilagineous, rimose-areolate, 

 and granulate, glaucescent (often greenish-soredliferous) ; apoth. ele- 

 vated on a thalline stratum which constitutes a thick, mostly entire spu- 

 rious margin, becoming convex, and excluding the obscure proper mar- 

 gin, fuscous-reddish. Lecidea, Ach. Syn. p. 40. Lecanora, Fee, Crypt. 

 Exot. p. 116. 



Trunks of cedars on the coast of New England. Pennsylvania, 

 Muhl. Extending to the tropics. 



21. B. rivulosa, Fr. Cr. tartareous, mouse-colored and paler, cov- 

 ering a fuscous-black hypothallus, which often decussates the crust ; 

 apoth. produced from the crust, from pale-fuscous becoming blackish, 

 whitish within, with a thin margin. Fr. Lichenogr. p. 271. Lecidea, 

 Ach. Lecanora falsaria, Ach. 



Rocks, especially in mountainous districts ; New England. Penn- 

 sylvania, Muhl. Northward to Arctic America, Rich. 



22. B. exigua, Chaub. Cr. of minute, confluent granules, smooth, 

 cartilagineous, cinereous-greenish ; decussated by lines of the black 

 hypothallus; apoth. submarginate, from pale-yellowish becoming fus- 

 cous. Fr. Lichenogr. p. 278. Lecidea varians, Ach. Syn. p. 38. 

 Tuckerm. Lich. N. E. I. c. L. versicolor, Schwein. in Hals. Lich. N. 

 Y. I. c. 7 



Smooth bark ; New England. New York, Halsey ? Pennsylvania, 

 Muhl. 



