verrucaria] verrucariace^ 281 



Dafydd, Carnarvonshire ; Airyholme Wood, Cleveland, Yorkshire ; 

 Ben Lawers, Perthshire ; Cork ; Blackwater liridge, Killarney, Kerry. 



Var. nigrata Leight. Lich. Fl. ed. 3, p. 449 (1879).- Tliallus 

 blackish-brown. Perithecia larger than in the species, immersed. 



Hah. On stones in running water. — B. M. Chedworth, Gloucester- 

 shire (the only locality). 



11. V. degenerascens Nyl. Ms. in Larb. Lich. Hb. n. 200. — 

 Thallus dark-brown, moderately thick, subdeterminate, mucila- 

 ginous when moist, continuous, then irregularly cracked, not 

 distinctly areolate. Perithecia minute, semi-immersed, slightly 

 depressed round the prominent ostiole ; perithecial wall black, 

 entire, thick above, continued beneath the base by a thinner 

 layer; spores somewhat oblong, narrower at one end, 0,017- 

 rarely -20 mm. long, 0,005-7 mm. thick. 



Exsicc. Larb. Lich. Hb. n. 200. 



Differing from V. Imvata in the smooth superficially cracked 

 thallus and in the smaller spores. 



Hah. On rocks. — B. M. Lough Feagh, Connemara, Galway (the 

 only localitj^). 



12. V. margacea Wahlenb. Fl. Lapp. p. 465 (1812).— Thallus 

 olive- or greyish-brown, thin, smooth, somewhat shining, con- 

 tinuous, eff'use or determinate. Perithecia moderate in size, 

 immersed in the thallus, becoming emergent, opening by a pore, 

 the perithecial wall dimidiate, or thinly developed under the base ; 

 spores ellipsoid or oblong, rather large, 0,024-35 mm. long, 

 0,010-16 mm. thick; hy menial gelatine wine-red with iodine. — 

 Cromb. Lich. Brit. p. Ill (excl. vars.) ; Leight. Lich. Fl. p. 416 ; 

 ed. 3, p. 446 (excl. vars.). V. suhmersa Borr. in Sm. Engl. Bot. 

 Suppl. t. 2768 (1833). F. Leighionii Hepp Flecht. Eur. n. 95 

 (1853) ; Mudd Man. p. 287 pro parte. Thelotrema margacea 

 Wahlenb. ex Ach. Meth. Supp. p. 30 (1803). 



On moist rocks often about the margins of streams. — Distr. 

 Rather rare throughout the British Isles. — B. M. Trefriw Falls, 

 Bettws-y-Coed, Carnarvonshire ; Craig Tulloch, Blair Athole and 

 Ben Lawers, Perthshire ; Morrone, Braemar, Aberdeenshire ; near 

 Ballinhassig, Cork; Caher Mts., Kerry. 



13. V. latebrosa Koerb. Syst. Lich. Germ. p. 349 (1855).— 

 Thallus reddish-grey, effuse, thin, faintly areolate. Perithecia 

 moderate in size, somewhat shining black, sessile more or less 

 covered at the base by the thallus ; perithecial wall dimidiate ; 

 spores usually 8 in the ascus, large, ellipsoid, becoming slightly 

 brownish, 0,030-35 mm. long, 0,012-15 mm. thick. — Leight. 

 Lich. Fl. ed. 3, p. 448. 



Exsicc. Larb. Lich. Hb. n. 237. 



Nearly allied to the preceding but with a less gelatinous thallus 

 and more emergent perithecia. 



