220 GRAPHIDEI [ARTHOTHELirSI 



thecia innate, immarginate, roundish cr somewhat elongate and 

 irregular ; asci ovat«-pyriform, thickened at the apices ; spores 

 ovate-elUptical, septate then muriform, colourless or brownish ; 

 paraphyses indistinct, branched, coherent. 



With the general characters of Arthonia, but differing in the 

 muriform spores. 



1. A. dispersum Mudd Man. p. 252, t. 4, f. 99 (1861).— 

 Thallus greyish-white or cream-coloured, thin, membranaceous, 

 smooth. Apothecia small, innate, plane, simple or minutely 

 radiate, congregate in small groups, brownish-black ; spores 

 oblong, muriform, colourless, 0,021-27 mm. long, 0,010-15 mm. 

 thick ; hymenial gelatine blue, the asci wine-red, with iodine. — 

 OpegrapTia dispersa DC. Fl. Franc, p. 308 (1805) pro parte (fide 

 Nyl. in Mem. Soc. Sci. Nat. Cherb. ir. p. 93 (1856) ). Arthonia 

 dispersa Duf. in Journ. Phys. Ixxxvii. p. 203 (1818) ; Carroll in 

 Nat. Hist. Rer. vi. p. 532 (1859). A. anastomosans Cromb. Lich. 

 Brit. p. 103 (1870) ; I^ight. Lich. Fl. p. 402 ; ed. 3, p. 425. 



A. radiata var. anastomosans Ach. Lich. Univ. p. 146 (1810). 



Hob. On the smooth bark of trees, chiefly young oaks and hazel. — ■ 

 Distr. Bare in S. England and S. Ireland. — B. M. Near ITllacombe, 

 Bovey Tracev, Devon; near Bantry Bay. Cork; Tore Mt.. Croghan, 

 Old Dromore and Eagle's Xest, Eillarney, Kerry. 



. 2. A. spectahile Massal. Eic. Lich. p. 54 (1852). — Thallus 

 whitish, effuse, thin, unequal, subfarinaceous. Apothecia brown- 

 ish-black, rather large, angularly roundish, often surrounded by 

 a spurious thaUine margin, scattered or crowded and subcon- 

 fluent, internally dark-coloured; spores oblong, septate, muri- 

 form, colourless, becoming brown, 0,030-36 mm. long, 0,015 mm. 

 thick ; hymenial gelatine usually blue then wine-red with iodine. — 

 Arthonia spectahilis Flot. ex IMassal. I. c. ; CarroU in Journ Bot. 

 wi. p. 100 (1868); Cromb. Lich. Brit. p. 103; Leight. Lich. Fl. 

 p. 402 ; ed. 3, p. 425. 



Hah. On trees. — Distr. Bare in S. England, Wales and S. Ireland. — 



B. M. Dartmoor, Devon; Dolgelly, Merioneth, Croghan, Killamey, 

 Derrv. 



GRAPHIDACE^. 



Thallus crustaceous. Algal cells Trentepohlia, or rarely 

 Pahnella. Apothecia usually linear {lirellx), rarely oblong or 

 oval, simple or branched, sessile or erumpent, marginate ; para- 

 physes simple or branched; asci elongate-clavate, spores simple 

 or variously septate or muriform, colourless or coloured. 



The more distinctly elongate apothecia, which have a well- 

 developed proper margin, distinguish Graphidacece from the two 



