LECANORA | LECANORACEX: 331 
90. L. Prevostii Th. Fr. Lich. Scand. p. 288 (1871).—Thallus 
effuse, thin, continuous, generally tartareous, greyish or whitish 
or pale flesh-coloured (K —, CaCl—). Apothecia minute, deeply 
immersed, often irregular in outline, concave, the disc pale flesh- 
coloured, the proper margin connivent, surrounded by and 
distinct from the thalline margin ; paraphyses coherent, slender, 
septate ; spores ellipsoid, 14—22 » long, 9-11 » thick ; hymenial 
gelatine blue then quickly wine-red with iodine.—Leight. Lich. 
Fl. ed. 3, p. 198 ; Cromb. Monogr. i. p. 478. LL. epulotica var. 
Prevostii Nyl. Lich. Scand. p. 189 (1861); Cromb. Lich. Brit. 
p. 05; Leight. Lich. Fl. p. 212. Gyalecta Prevostii Fr. Lich. 
Eur. p. 197 (1831). G. geoica Leight. Angioc. Lich. p. 87, t. 15, 
fig. 1 (1851) (non Wahlenb.). ; 
Easily overlooked owing to the rather neutral colour of the thallus 
and the inconspicuous apothecia, which are either immersed in pits 
or more rarely level with the surface. 
Hab. On calcareous rocks in hilly or mountainous districts.— 
Distr. Rare in W. and N. England and the Grampians, Scotland. 
—B. M. Bathampton Downs, Somerset; Ease Gill, near Leek, 
Lancashire; Levens, Westmoreland; Craig Tulloch, Blair Athole, 
Perthshire ; Craig Guie, Braemar, Aberdeenshire. 
Form melanocarpa Stizenb. Lich. Helv. p. 129 (1882).— 
Apothecia becoming more prominent and darker, with the 
thalline margin obliterated—Cromb. Monogr. i. p. 479.  L. 
gibbosa subsp. lacustris var. punctata Cromb. Lich. Brit. p. 55 
(1870)? L. gibbosa f. punctata Leight. Lich. Fl. p. 210 (1871)? 
ed. 3, p. 196% Lichen punctatus Sm. Engl. Bot. t. 450 (1798) ? 
(Dicks.?) Urceolaria Acharii var. cyriaspis Ach. Meth. Lich. 
p- 151 (1803); Hook. in Sm. Engl. Fl. v. p. 172 pro parte. 
U. cyrtaspis S. F. Gray Nat. Arr. i. p. 458 (1821)? Aspieilia 
epulotica var. punctata Mudd Man. p. 161 (1861). Hymenelia 
Prevostii var. melanocarpa Krempelh. Fl. Bayer. p. 167 (1861) 
nomen. 
Searcely distinguishable from the species. Lichen punctatus, 
figured and described in English Botany from a specimen collected at 
Ludlow, scarcely accords with this variety, and Sowerby’s specimen 
in Hb. Brit. Mus. is from Teesdale, and hardly differs from the species 
(cf. L. campestris. p. 274). Specimens from Somerset (Bathampton 
Downs) seem to be wholly Verrucaria integra Carroll. 
Hab. On caleareous rocks in hilly or mountainous districts.— 
Distr. Rare in N. England and the Grampians, Scotland.—B. M. 
Teesdale, Durham; Craig Tulloch, Blair Athole, Perthshire. 
Var. affinis Nyl. ex. Stizenb. 1. c.—Thallus thin, somewhat 
similar to that of the species or reddish-flesh-coloured. Apothecia 
minute, becoming more prominent, the thalline margin per- 
sistent ; spores similar to those of the species or more broadly 
ellipsoid, 14-18 y» long, 9-13 p thick.—Cromb. Monogr. i. p. 479. 
