228 LICHENACEI. [EVEPNIA. 



Series IV. Phyllodei Nyl. Mem. Soc. Cherb. ii. (1854) 

 p. 12; Syn. i. p. 315. 



Thallus foliaceous, depressed, lobed or variously laciniate or stel- 

 late, rarely fruticulosely ciespitose, corticate on both sides, or some- 

 times only on the upper surface ; beneath discolorous, very rarely 

 subconcolorous, affixed to the substratum by rhizinso, internally 

 woolly, very rarely solid. Apothecia either peltiforrn or lecanorine, 

 or lecideine and gyrose : spores usually 8na3, ellipsoid or fusiform, 

 simple or variously divided ; paraphyses either discrete or conglu- 

 tinate. Spermogones innate, with jointed sterigmata ; spermatia 

 acicular or cylindrical, straight. 



A well-marked Series comprising the best developed of all lichens, 

 many of which from their large size are conspicuous objects in their 

 various habitats. Though the tribes are as to thallus and fructiti cation 

 rather diverse, yet there are mutual links by which in both of these 

 respects they are closely connected. The foliaceous and usually horizontal 

 appressed thallus at once distinguishes it from the preceding and the 

 following Series. 



Tribe XIII. PARMELIEI Nyl. Flora, 1869, p. 445 

 (cfr. Cromb. Grevillea, v. p. 77). 



Thallus horizontally expanded, or occasionally erect or ascending, 

 laciniate or laciniato-lobed, beneath discolorous ; gonidial layer con- 

 sisting of true gonidia. Apothecia parmeleine, sessile or sub- 

 pedicellate ; spores usually 8na3, ellipsoid or rarely oblong, simple, 

 colourless ; paraphyses not discrete. Spermogones innate ; sterig- 

 mata pauci-articulate ; spermatia acicular, fusiformi-incrassate at 

 either apex, or very rarely cylindrical, long and arcuate. 



According to Nylander's recent arrangement, this tribe includes four 

 genera, of which Ecernio}ms occurs only in subtropical America. Most of 

 the European species of the other genera are met with in Great Britain. 



41. EVERNIA Ach. Lich. Univ. (1810) p. 84 ; Nyl. Syn. i. (1860) 

 p. 283, Flora, 1869, p. 445. Thallus erect or ascending, or pros- 

 trate or pendulous, applanate or somewhat rounded, laciniately 

 divided or very much branched, opaque or subopaque, somewhat 

 soft or flaccid, rhizinse none or very few ; medullary layer without 

 any cavities, arachnoid or partly chondroid, cortical layer thin, 

 formed of obliterated cells. Apothecia lateral, with entire thalline 

 margin ; hypothecium colourless, thecac small, clavate ; spores 8noe, 

 small, simple, colourless ; hymenial gelatine bluish with iodine. 

 Spermogones immersed or somewhat superficial ; spermatia acicular, 

 straight, somewhat acute at the apices, and towards either apex 

 very thinly fusiformi-incrassulate. 



Nylander with most authors placed Evernia near Alectoria, on account 



