LRCANORA.] LECANO-IECIDEEI. 477 



S.W. ri(!laii(l.— ]]. :\r. : Fin<ilo IJiidoo, near Chaj?ford, S. Devon ; Dol- 

 <>-elly and JMiiw^^-ruiddcm, Mi-riom^thsliire ; rx^ttwys-y-cood, Dcnljifrlisliire; 

 Island of An^lcsca : Wrekin Hill, Shropshire; JCglostonc, J)iiriiani; 

 8tavcley, Kenihil, AN^estmoreland ; jjamplugh, Cumberland. King's I'ark, 

 Edinburji-h; ]5en Lawers and Crai^^ Tulloch, IVrthshire; Glen Callater 

 and Morrone, llrauniar, Aberdeenshiro. Crogiiani and Mangerton, co. 

 Iverry. 



Form atrata Cromb. Grcvillca, xix. (1891) p. 58. — Thallus only 

 hero and there sparingly visible upon the predominating liypotballiis. 

 Apothccia scattered, minute. — Gi/ulccta atrata Ach. Vet. Ak. Haudl. 

 1808, p. 229. 



A rudimentary, tliongli apparently permanent condition in which 

 scanty traces of a ferruginous thallus are seen only around the apotbecia, 

 ■which in the British specimens are numerous. 



Hab. On quartzose rocks in an alpine locality. — Distr. Only very 

 sparingly on one of the N. Grampians, Scotland. — B. M. : Mornme, 

 Braemar, Ab-erdeensbire. 



170. L. lacustris Fr. fil. A^et, Akad. Hand], vii. (1867) p. 24.— 

 Tliallus determinate or subeft'use, thin, smooth, rimuloso-difl'ract, 

 pale testaceous or ochraceous (K — , CaCl— ). Apotbecia minute, 

 urceolato-innate, reddish testaceous or brownish ; the thalliue 

 margin tumid or usually little distinct ; spores Sute, ellipsoid, 0,0 IS- 

 IS mm. long, 0,006-9 mm. thick ; paraphyses not discrete, slightly 

 brownish or yellowish at the apices ; hypothecium colourless ; 

 hymenial gelatine bluish, then sordid-wine-red or tawny with 

 iodine. — Cromb. Grevillea, i. p. 172 ; Leight. Lioh. Fl. ed. 3, p. 195 

 (excl. forma jninctata). — Lecanora gihhosa forma lacustris Leight. 

 Lich. Fl. ed. i. p. 210 ; subsp. lacustris Cromb. Lich. Brit. p. 55. 

 Lichen lacustris With. Arr. ed. 3 (1796) iv. p. 21, t. 31. fig. 4. 

 Urceolana Acharii Gray, Nat. Arr. i. p. 457 ; Hook. Fl. Scot. ii. 

 p. 47 ; Sm. Eng. Fl. v. p. 172 ; Tayl. in Mack. Fl. Hib. ii. p. 132 

 (incl. var. /3). Liclien Acharii Westr. Eng. Boc. t. 1087. Aspicilia 

 epulotlca Mudd, Man. p. 161 pro maxima parte. — Brit. Exs.x Cromb. 

 n. 71. 



The thallus is normally pale, almost white, but is usually more or less 

 ochraceous from being tinged with peroxide of iron. It often spreads 

 extensively over the substratum and is at times semi-aquatic. The 

 apotbecia, which are numerous and often crowded, are at first minute, 

 immersed, rarely at length prominent, occasionally in age becoming sub- 

 moderate, plane, and distinctly margined by the thallus. Occasionally 

 the spores are rather thicker, 0,012 mm., when it is Lecidea subepidutica 

 Nyl. Mem. Soc. Cberb. t. v. p. 337, a state which occurs also in Great 

 Britain and Ireland. — Var. /3. cyrtaspis (Ach.) Cromb. Grevillea, xix. 

 p. 58, does not belong to this species (cfr. Fr. fil. Licli. Scand. p. 288). 



Hub. On rocks (often inundated) in streams in upland and subalpine 

 districts. — Distr. Only here and there, though plentiful where it occurs, in 

 Great Britain and Ireland. — B. M. : Lyndbur^t Moor, New Forest, Hants ; 

 Dartmoor, Devonshire ; Withiel, Cornwall ; Naniiau, Dolgelly, and near 



