16 LECANO-LBCIDEBI [lECIDEA 



subimbrioate. Their margins are at times persistently whitish (form 

 alhomarginata Miill. Arg. in Flora Ixiv. p. 88 (1881), Cromb. in 

 GrevUlea xxii. p. 59). In age the thallus becomes more or less 

 dealbate and subpruinose (form cretacea MtlU. Arg. in Bull. Soc. 

 Murith. fasc. x. p. 55, 1881). The spermogones not unfrequently 

 have bacillar spermatia, 0,05-6 mm. long, 0,0008 mm. thick 

 (fide Nyl. Lich. Env. Par. p. 77). Our British specimens are for the 

 most part well fertile. 



Kah. On cretaceous and calcareous soU in hilly and mountainous 

 districts. — Bistr. Only a few localities in England, N. Wales, and the 

 Highlands of Scotland; not seen from Ireland. — B. M. Epsom 

 Downs, Surrey ; Newhaven, Sussex ; Gogmagog HUls, Cambridge ; 

 Great Orme's Head, Carnarvonshire; Teesdale, Durham; Island of 

 Lismore, Argyll ; Craig Calliach and Ben Lawers, Perthshire ; Clova 

 Mts., Forfar. 



11. L. lugubris Sommerf. Suppl. Fl. Lapp. p. 143 (1826) pro 

 parte; Nyl. in Bot. Not. p. 176, fig. 6b (1852).— Thallus indeter- 

 minate, thickish, minutely squamulose, granulose-concrete, broken 

 up into crumb-like portions, brownish- or chocolate-grey (K — , 

 GaCl — ); hypothallus black, apothecia small or submoderate, 

 superficial, plane, margined, opaque, black, within greyish-white, 

 the margin thickish, prominent, entire, persistent, occasionally 

 subflexuose ; paraphyses slender, very loosely coherent, thickened 

 at the apices ; epithecium dark-green ; hypothecium blackish- 

 brown ; spores spherical, halonate, 0,008-9 mm. in diam. ; hyme- 

 nial gelatine bluish with iodine. • — Lindsay in Quart. Journ. 

 Microsc. Sci. v. p. 177, t. 11 (1857); Cromb. Lich. Brit. p. 85; 

 Leight. Lich. Fl. p. 255 ; ed. 3, p. 246. Schsereria lugubris Koerb. 

 Syst. Lich. Germ. p. 232 (1855) ; Mudd Man. p. 213, t. iv. fig. 78 

 (1861). 



Exsicc. Cromb. n. 91 ; Mudd n. 183. 



Nylander has discussed and determined the nomenclature of 

 this plant (Lich. Scand. pp. 238, 293 (1861)), Sommerfelt's original 

 specimen having included two distinct species, L. caudata Nyl. 

 and L. lugubris. It is well characterized by the spores which are 

 uniseriate in the narrow, elongate-cylindrical asci. The thallus, 

 which usually spreads extensively, is composed of very minute or 

 subminute, crowded, sublobulate, more or less convex squamules, 

 eventually obliterating the hypothallus. The squamules are rather 

 larger planer and more discrete when the plant is muscicolous. The 

 numerous hypothecia are generally somewhat scattered. ' The spermo- 

 gones, not often visible, are punctiform, black, with short, cylindrical, 

 straight spermatia. 



Hah. On rocks and boulders, granitic and schistose, very rarely 

 inorusting mosses, in mountainous districts. — Bistr. Found only in 

 N. Wales, N. England and among the Grampians, Scotland ; not 

 seen from Ireland. — B. M. Cader Idris, Merioneth ; Ayton, Kildale 

 Moor, Cleveland, and Cronkley Scar, Yorkshire; High Force, Tees- 

 dale, Durham ; Ben Lawers, Craig Tulloch and Glen Fender, Blair- 

 Athole, Perthshire ; Morrone, Braemar, Aberdeenshire. 



Var. lugubrior A. L. Sm. — Thallus more or less minutely 

 granular, effuse, not squamulose, greyish- or dark-brownish on a 



