opbgrapha] graphidace^ 243 



FI. ed. 3, p. 408. Verrucaria horistica Leight. Lich. Fl. p. 451 

 (1871) ; ed. 3, p. 482 & in Grevillea i. p. 60, t. 4, f. 1. 



Well characterized by the presence of soredia, and usually by the 

 numerous, prominent, intersecting black lines. 



Hah. On rocks. — Distr. Bare in the Channel Islands, N. Wales 

 and N. England. — B. M. Port Grorey, Sark; Boulay Bay, Jersey; 

 Cader Idris, Merioneth ; Llyn Cwlyd, near Capel Curig, Bettws-y- 

 Coed and Trefriw, Carnarvon ; above Scroggs Bridge, Westmoreland. 



20. 0. csesariensis Nyl. in Flora li. p. 477 (1868).— Thallus 

 white, indeterminate, thin, often only slightly developed. Apo- 

 thecia prominent, cylindrical, simple, subflexuose about 1 mra. 

 in length ; disc slit-like ; paraphyses conglutinate ; hypothecium 

 and epitheoium dark-brown or blackish ; spores oblong-fusiform, 

 colourless, 5-septate, 0,017-21 mm. long, 0,004 mm. thick. — 

 Cromb. Lioh. Brit. p. 99; Leight. Lich. Fl. p. 383; ed. 3, 

 p. 406. 



Exsicc. Larb. Lich. Hb. n. 353 <fe Lich. Csesar. n. 43 (?) 

 (improperly developed). 



Hab. On quartzose rocks. — Distr. Bare in the Channel Islands 

 and S. England. — B. M. Sark ; near Eozel, La Coupe, Noirmont and 

 L'Etacq (?) ; Jersey ; the Lizard and Pentire, St. Minver, Cornwall. 



21. 0. lithyrga Ach. Lich. Univ. p. 247 (1810) pro parte 

 & Syn. p. 72 (1814) (incl. var. steriza). — Thallus greenish- 

 grey, dark-coloured, or whitish, sometimes wanting. Apothecia 

 roundish, elongate-ovoid or usually elongate and slender, simple 

 or sometimes divided, rarely stellately arranged or in groups ; 

 disc narrow ; margins incurved ; paraphyses slender, distinct, 

 not discrete ; spores narrow, fusiform, colourless, 5-7-septate, 

 0,020-28 mm. long, 0,003, rarely 0,004-5 mm. thick ; spermogones 

 with straight or slightly-bent spermatia, 0,004-5 mm. long, 

 0,001 mm. thick. — 0. vulgata vars. lithyrga & steriza Nyl. Lich. 

 Scand. p. 255 (1861) ; f. lithyrga Stiz. in Nov. Act. Acad. 

 Leop.-Carol. xxxii. 4, p. 7, t. 1, f. 2 (1865) ; Cromb. Lich. Brit, 

 p. 99; Leight. Lich. Fl. p. 385; ed. 3, p. 408; f. steriza 

 Leight. II. c. 



Exsicc. Larb. Lich. Hb. nos. 318, 354; Lich. Csesar. n. 42. 



Distinguished by the usually slender thread-like apothecia and by 

 the narrow spores resembling those of 0. vulgata. 



Hah. On rooks. — Distr. Bare in the Channel Islands, Central 

 England and S. and W. Ireland. — B. M. St. Brelade's Bay and Noir- 

 mont, Jersey ; Crogham, Killarney, Kerry. 



22. 0. lithyrgodes Nyl. in Flora Iviii. p. 106 (1875). — 

 Thallus reddish-brown, thin, continuous. Apothecia minute, 

 scattered, shining-black, sessile, oblong or linear-oblong; disc 

 narrow ; margins thickish, round, inflexed ; spores elongate, 



R 2 



