220 ORAPHIDEI [aRTHOTHELIUM 



thecia innate, immarginato, roundish or somewhat elongate and 

 irregular ; asci ovate-pyriforni, thickened at the apices ; spores 

 ovate-elliptical, septate then niuriforni, colourless or brownish ; 

 paraphyses indistinct, branched, coherent. 



With the general characters of Arthonia, but differing in the 

 muriforni spores. 



1. A. dispersuin 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. — 

 Opegraj^ha dittjjersa DC. Fl. Franc, p. 308 (1805) pro parte (fide 

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

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

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

 Brit. p. 103 (1870) ; Leight. Lich. Fl. p. 402 ; ed. 3, p. 425. 



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



Hah. On the smooth bark of trees, chiefly 3'oung oaks and hazel. — 

 Distr. Eare in S. England and S. Ireland. — B. M. Near Ullacombe, 

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

 Old Dromore and Eagle's Nest, Killarney, Kerry. 



2. A. spectabile Massal. Ric Lich. p. 54 (1852). — Thallus 

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

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

 a spurious thalline 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 Massal. I. c. ; Carroll in Journ Bot. 

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

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



Hob. On trees. — Distr. Eare in S. England, Wales and S. Ireland. — 



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

 Derry. 



GnAVRWACEM. 



Thallus crustaceous. Algal cells Trentepohlia, or rarely 

 Palmella. Apothecia usually linear (lirellse), 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 ha^e a well- 

 developed proper margin, distinguish Grajphidaceoi from the two 



