38 EYERNTA. 



a, upon trees throughout the eastern United States. Muhlen- 



berg Catal 1818. West Coast, Menzies. b, on the earth, in 



alpine districts. Arctic America, Herb. Hook. Rocky Mount- 

 ains, Hall c, shrubs and rocks in sub-alpine districts, and 



descending. Arctic America, Richardson. New England mount- 

 ains, Tuckerman. Rocky Mountains, Hall. British Columbia, 

 Macoun. 



IV. EVERNIA, Ach., Mann. 



Apothecia scutellseform, concave, then often dilated and 

 cyathiform j the disk coloured differently from the thallus. 

 Spores sub-ellipsoid, simple, colourless. Spermatia oblong, 

 or staff-shaped, thickened either at one, or both ends, or 

 cylindrical 5 upon sparingly branched sterigmas. Thallus 

 fruticulose, at length often pendulous ; angulose-teretish or 

 foliaceous-compressed; softish; glaucous, straw-coloured, or 

 lemon coloured ; the medullary layer cottony j or, the fila- 

 ments now coalescing, and finally solid. Anatomy of the 



thallus in Schwend. Untersuch, 1. c. 2, p. 157, t. 4, fig. 

 13-15, t. 5,/. 1-6. 



* Medullary layer solid. 



1. E. Trulla (Ach.) Mont. ; thallus tufted, membranaceous, 

 prostrate and assurgent, dichotomously linear-laciniate, chan- 

 nelled, naked on both sides ; greenish-glancescent above ; pale- 

 brownish and violaceous-black beneath ; ' apothecia marginal, 

 ample, cyathiform, wrinkled and plaited ; the concave disk brown. 



Spores ellipsoid, ^^ mic.' Mont. Chil. p. 74. Parmelia, Ach. 



Meth. p. 256, t. 4,/. 6 ; L. U. p. 496. Parmelia (Evernia) denu- 

 data, Hampe in Linncea, 1843, p. 122. Everniopsis Trulla, 

 Nyl Syn. p. 374. 



On the earth? Central and South America. Mexico, Ny- 



lander. Perhaps best comparable with E. furfuracea, the 



structural thalline difference of which may possibly be regarded 

 as mediated by the next species. 



* * Medullary layer cottony; but coalescent, more or less, into 

 solid cords. . 



2. E. vulpina (L.) Ach.; thallus tufted, erect, angulous- 

 teretish or here and there compressed, lacunose, dichotomously 



