262 CYCLOCARPINEA: [LECANORA 
circumference or of imbricate squamules, pale-yellowish straw- 
coloured ; sometimes pruinose ; beneath pale towards the centre, 
bluish-black towards the edges (K — ). Apothecia moderate in 
size, the disc reddish-flesh-coloured, the margin thin, entire or 
becoming crenate and flexuose; spores ellipsoid, 9-12 pw long, 
4-6 p thick.—Cromb. Monogr. i. p. 352. Lichen chrysoleucus 
Sm. in Trans. Linn. Soc. i. p. 82, t. 4, fig. 5 (1791). Squamaria 
chrysoleuca Leight. Lich. Fl. ed. 3, p. 158. 
Considered by Crombie as doubtfully British; it has not again 
been collected at Ben Brecht. It occurs both in Scandinavia and 
the Alps. 
Hab. On granite and schistose rocks in alpine districts.—Distr. 
Recorded by Leighton (1. c.) from Ben Brecht, Argyll. 
5. L. pruinosa Chaub. in St. Am. Fl. Agen. p. 495 (1821).— 
Thallus orbicular, continuous, effigurate at the circumference, 
whitish and subfarinaceous, the outer squamules plicate and 
crenate (CaCl + red). Apothecia small, the dise brownish and 
grey-pruinose, the thalline margins prominent, entire or sub- 
crenulate ; spores ellipsoid, 10-13 p long, 5—6 p thick.—L. pruini- 
fera Nyl. in Bull. Soc. Bot. Fr. xiii. p. 368 (1866) note ; Cromb. 
in Journ. Bot. xx. p. 274 (1882) & Monogr. 1. p. 355. 
Differs from LD. lentigera in the farinaceous surface and in the 
pruinose apothecia. The surface ‘ powder”’ is largely composed of 
crystals of oxalate of lime. 
Hab. On calcareous rocks.—B. M. Cleve Hill, Somersetshire (the 
only British locality). 
6. L. gelida Ach. Lich. Univ. p. 428 (1810).—Thallus 
normally orbicular, up to 5 cm. or more in diameter, often some- 
what irregular, closely appressed, cartilaginous, areolate in the 
centre, sometimes with greenish soredia, efligurate at the circum- 
ference, the radii narrow, branched, widening outwards and 
crenate at the tips, dull-white to cinerous-grey (K + yellow, 
CaCl + red), cephalodiiferous, the cephalodia forming small 
brownish or flesh-coloured orbicular radiate patches scattered 
over the thallus. Apothecia moderate in size, adnate, the disc 
flesh-coloured, the margin thick, entire; paraphyses slender, 
branched and septate at the tips; spores ellipsoid, 14-18 yp long, 
6-8 p thick.—Hook. FI. Scot. ii. p. 50; Tayl. in Mackay FI. 
Hib. ii. p. 140; Cromb. Monogr, i. p. 355. Lichen gelidus L. 
Mant. p. 133 (1767); Dicks. Pl. Crypt. fase. ii. p. 19; With. 
Arr. ed. 3, iv. p. 26; Engl. Bot. t. 699. Placodium gelidum 
S. F. Gray Nat. Arr. i. p. 448 (1821). Squamaria gelida Hook. 
in Sm. Engl. Fl. v. p. 195 (1833); Mudd Man. p. 129; Cromb. 
Lich. Brit. p. 45; Leight. Lich. Fl. p. 176; ed. 3, p. 159 (inel. 
f. dispersa). 
