204 CYCLOCARPINEX | PLACODIUM 
suggested (Flora lxvi. p. 106) that this plant may be the original 
Lichen murorum Hoftm. : 
Hab. On walls in lowland districts.x—Dvistr. Local in S.W. and 
E. England.—B. M. Shoreham, Kent; near Cirencester, Gloucester- 
shire; Milton Church, Cambridgeshire; Anglesea. 
10. Pl. cirrochroum Hepp Flecht. Eur. n. 398 (1857).— 
Thallus small, orbicular, closely adnate, often imperfect, radiate- 
stellate, the lacinie narrow and convex or somewhat wider 
and more contiguous, crenulate at the tips, bright orange-yellow, 
crustaceous-areolate and sometimes darker and poorly developed 
at the centre, bright orange-yellow, citrine within and dotted. 
with citrine soralia (K + purplish). Apothecia minute, orange- 
yellow, the thalline margin subentire; spores oblong-ellipsoid, 
13-18 p Jong, 5-6 » thick.—Cromb. in Journ. Bot. xii. p. 147 
(1874); Leight. Lich. Fl. ed. 3, p. 161.  Lecanora cirrochroa 
Ach. Syn. Lich. p. 181 (1814); Cromb. Monogr. i. p. 363. 
L, linearis Tayl. in Mackay Fl. Hib. ii. p. 260 (1836) (young 
state ?). 
Ezsicc. Johns. n. 99. 
Characterized by the small round citrine soralia dotted over the 
thallus. The British plants are sterile. The spores are long in 
relation to their width, though I have not been able to see any up to 
18. The paraphyses are slender, but more or less clavate and septate 
at the tips. 
Hab. On rocks, mostly caleareous, in maritime and inland districts. 
—Distr. Rather rare throughout the British Isles, though commoner 
in western districts—B. M. Anstey’s Cove, Torquay and Sidmouth, 
Devon; Yatton and Weston-super-Mare, Somerset; Great Orme’s 
Head, Carnarvonshire; Silverdale, Lancashire; Dovedale, Derby- 
shire; Arnbarrow, near Kendal and Milnthorpe, Westmoreland ; 
Alston, Cumberland ; I. of Lismore, Argyll; Craig Tulloch, Blair 
Athole, Perthshire ; Dunkerron, Kerry. 
Var. obliterans A. L. Sm.—Thallus smaller, less distinctly 
radiate, or the lacinize sometimes obsolete, varying in colour from 
ochraceous to deep tawny-yellow, the soredia citrine or somewhat 
tawny-yellow, less effuse than in the spegies. — Placodium 
obliterans Nyl. in Flora lvii. p. 7 (1874). Specimen not seen. 
Nylander has suggested the varietal affinity of this plant. It 
agrees with the species in the presence of soredia, a rather unusual 
character in this genus, 
Hab, On schistose rocks, Caithness. 
Thallus ovbicular, entirely leprose. 
11. Pl. xantholytum Nyl. Lich. Env, Paris, p. 46 (1896).— 
Thallus orbicular, continuous, crenate at the circumference, 
everywhere leprose, golden-yellow or greenish-yellow, white within 
(K + rose-crimson). Apothecia and spermogones unknown.— 
