244 GRAPUIDEI [OI'EGRAPHA 



fusiform, 7-soptate, 0,032 mm. long, 0,000 ram. thick ; spormo- 

 gones with arcuate spermatia. — Leight. Lich. Fl. p. 409. 

 Exsicc. Larb. Lich. Hb. n. 191. 



Somewhat similar to the following in the form and scptation of 

 the spores, but differing in the thallus and in the constantly minute 

 apothecia. 



Hah. On rocks. — Distr. Eare in W. Ireland. — B. M. Lough Muck, 

 Oonnemara, Galway. 



23. 0. Leightonii Cromb. ex Leight. Lich. Fl. p. 385 (1871). 

 — Thallus effuse, varying in thickness, pulverulent, greyish-green 

 or chalky-white, sometimes wanting. Apothecia prominent, 

 linear-elliptical, usually rather long and stout, straight or 

 flexuose, simple or occasionally forked ; disc becoming somewhat 

 expanded and naked or greyish-pruinose ; margins at first thick 

 and elevated, becoming thinner ; spores subclavate, fusiform, 

 colourless, sometimes becoming brownish, straight or bent, 

 5-7-septate, usually 6-septate, the central cell somewhat larger, 

 0,025-31 mm. long, 0,005-6 mm. thick. — Leight. op. cit. ed. 3, 

 p. 409. 0. saxatilis Leight. in Ann. Mag. Nat. Hist. ser. 2, 

 xiii. p. 89, t. 5, f. 3 (1854) (excl. syn.) (non DC); Mudd Man. 

 p. 227 (excl. syn.). 



Exsicc. Mudd n. 202. 



Easily distinguished by the form and septation of the spores. 

 When well-developed, it is one of our most beautiful species, the 

 prominent black fruits being in striking contrast with the light 

 coloured thallus. The apothecia are sometimes few and scattered or 

 numerous and lying in all directions, often arranged in a substellate 

 manner. 



Hab. On calcareous and sandstone rocks. — Distr. Eather un- 

 common throughout England, rare in Ireland, not yet recorded for 

 Scotland. — B. M. Saltash, Cornwall ; Ilsham, Torquay, Devon ; 

 Fulking, Sussex; Duntisborne and Barnsly Park, Gloucestershire; 

 Netley Abbey, Hants ; Donnington Castle, Berks ; The Bartons near 

 Ledbury, Herefordshire; Bartlow Church, Essex; Aberdovey, 

 Merioneth ; Earl's Barton, Northamptonshire ; Newton Wood, Cleve- 

 land, Yorkshire ; liillarney, Kerry. 



Spores 7- to multi-septate. 



24. 0. lyncea Borr. ex Hook, in Sm. Engl. Fl. v. p. 144 (1833). 

 • — Thallus white, tartareous, pulverulent, unequal. Apothecia 

 black, immersed, oblong or linear-oblong, short or elongate, 

 simple, curved, the disc open, plane, bluish-grey-pruinose ; 

 margins stout, elevated, wavy ; paraphyses indistinct ; spores 

 elongate-fusiform, colourless, about 7-septate, 0,022-30 mm. long, 

 0,004 mm. thick ; spermogones with oblong spermatia 0,004 mm. 

 long, 0,001 mm. thick.— Mudd Man. p. 229 ; Cromb. Lich. Brit, 

 p. 100 ; Leight. Lich. Fl. p. 386 ; ed. 3, p. 409. Lichen lynceus 

 8m. Engl. Bot. t. 809 (1800). Arthonia lyncea S. F. Gray Nat. 

 Arr. i. p. 479 (1821). Lecanactis lyncea Eschw. Syst. Lich. 



