192 LECANO-LECrOEEI [rHIZOCAKPOX 



convex ; hypothallus very distinct, often predominating. Apothecia 

 plane or tumid, situated between the areolae. — Mudd Man. 1. c. 

 Lichen atrovirens L. Sp. PI. p. 1607 (1753); Huds. Fl. Angl. 

 ed. 2, p. 525 ; Lightf. I. c. ; With. I. c. Lecidea atrovirens Hook. 

 Fl. Scot. /. c. ; S. F. Gray Xat. Arr. i. p. 465. Lecidea geo- 

 graphica var. atromrens Schser. Spicil. 7. c. ; Cromb. Lich. Brit, 

 p. 93 & Journ. Idnn. Soc. xxi. t. 9, f. 4 (1886); Leight. Lich. 

 Fl. p. 346 ; ed. 3, p. 373. 



Perhaps only a less developed thalline condition of the species. 

 When the areolae are thinly scattered and the hypothaUus pre- 

 dominates it is f. prototliallina Koerb. (I. c). The spermogones are 

 more frequent than when the thaUus is more developed, the 

 spermatia cylindrical, nearly straight. 



Mah. On rocks and boulders (calcareous excepted) in maritime and 

 mountainous districts. — Distr. No doubt similar to that of the species, 

 though seen from comparatively few localities, chiefly in Scotland. — 

 B. M. Eoughton, Cornwall ; Ben-y-gloe, Blair Athole, Perthshire ; 

 Portlethen, Kincardineshire ; Morrone, Braemar, Aberdeenshire ; 

 Hills of Applecross, Bossslure ; Letter Hill, Connemara, Galway. 



Tar. lecanorinum Floerke ex Koerb. 7. c. — Thalline areolae, 

 somewhat discrete and convex. Apothecia immersed in the 

 areolae, with a spurious margin ; spores usually halonate, 

 submuriform 0,030—40 mm. long, 0,011—16 mm. thick. — Lecidea 

 geograpliica var. cyclopica Xyl. Lich. Scand. p. 248 (1861); Leight. 

 Lich. Fl. I. c. ; f. cydopica ed. 3, p. 374. 



Exsicc. Johns, n. 398. 



Well distinguished by the somewhat longer spores and by the 

 character of the apothecia, which are single in each of the areolae and 

 appear as if lecanoroid from the spurioTis thalline margin. 



Hob. On slate rocks. — Distr. Bare in upland or mountainous 

 districts in X. England and the Grampians, Scotland. — B. M. 

 Lakeside, Ennerdale, Cumberland ; ilorrone, Braemar, Aberdeenshire. 



Tar. geronticum Th. Fr. Lich. Scand. p. 622 (1874).— Thalline 

 areolae subplane or convex, scattered or subcontiguous, somewhat 

 rugose, white, sabpulvemlent. Apothecia plane, immersed in 

 the areolae. — Lecidea atrovirens var. gerontica Ach. Meth. p. 45 

 (1803). L. geograpMca var. gerontica Kyi. Lich. Scand. p. 248 

 (1861) ; Cromb. Lich. Brit. I. c. ; Leight. Lich. Fl. p. 347 ; ed. 3, 

 p. 374. 



Well characterized by the colour of the more or less pulverulent 

 thaUus, whence Schserer (Spicil. pp. 124, 193) termed it var. 

 pulverulenta. It is rather interesting as being the only state of the 

 species which occasionally occurs on a calcareous substratum. 



Hob. — On quartzose, occasionally calcareous, boulders and stones 

 in mountainous regions. — Distr. Bare on the Grampians, Scotland. — - 

 B. If. Morrone, Braemar, Aberdeenshire ; Ben Nevis, Bossshire. 



7. Rh. viridiatrum Koerb. Syst. Lich. Germ. p. 262 (1855). — 

 ThaUus greenish-yellow, indeterminate, granular-areolate, the 



