22S LICHEXACFI. [eVERXIA. 



Series IV. Phyllodei Xyl Mem. Soc. Cherb. ii. (lSo4) 

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



Thallus foliaoeous. depressed, lobed or variously laciniate or stel- 

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

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

 subconcolorous, affixed to the substratum by rhizinpe, internally 

 woolly, very rarely solid. Apothecia either peltiform 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 

 aeicular 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 tlieir 

 various habitats. Though the tribes are as to thallus and fructitication 

 ratber 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 Xyl. Flora, 1869, p. 445 

 {cfr. C'romb. Grevillea, v. p. 77). 



Thallus horizontally expanded, or occasionall}' erect or ascending, 

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

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

 pedicellate ; spores usually Sua?, ellipsoid or rarely oblong, simple, 

 colourless ; paraphyses not discrete. Spermogones innate ; sterig- 

 mata pauci-articulate ; spermatia acicuhir, fusit'ormi-incrassate at 

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



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

 genera, of which iJrenu'opsi.^ occm's 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 ; Xyl. Syji. i. (1860) 

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

 trate or pendulous, applanate or somewhat rounded, laciniatel}' 

 divided or very much branched, opaque or subopaque, somewhat 

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

 auj' cavities, arachnoid or parth* chondroid, cortical layer thin, 

 formed of obliterated cells. Apothecia lateral, with entire thalline 

 margin ; hypothecium colourless, theca^ small, clavate ; spores Snx, 

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

 Spermogones immersed or somewhat sui)erficial ; spermatia aeicular, 

 straight, somewhat acute at the apices, and towards cither ape.x 

 very thinly fusiformi-iucrassulate. 



Njdander with most authors placed Evernia near Alectoria, on account 



