LECANORA. | LECANO-LECIDERI. 371 
Subgen. 7. EULECANORA Nyl. Not. Sillsk. pro F. et Fl. 
Fenn. Férh. n. s. v. (1866) p. 127.Thallus crustaceous, granulose 
or leprose, very rarely radiate. Apothecia lecanorine or lecideoid ; 
spores occasionally numerous, simple or variously septate, rarely 
brown; hymenial gelatine variously tinged with iodine. Spermo- 
gones with jointed or simple sterigmata and various spermatia. 
The largest subgenus of Lecanora and in several respects confluent 
- with the preceding subgenera. According to the structure of the apo- 
thecia and spermogones it is divided into different sections, most of which 
have been viewed as distinct genera by sporologists. 
A. Spores 8nz (rarely 8-16ne), polari-bilocular, b 
rarely simple or 1-septate, colourless ; 
hymenial geiatine, especially the thece, 9 
bluish with iodine. Spermogones with NAY 
jointed sterigmata and straight spermatia. 
(Eucaloplaca Fr. fil. Lich, Scand. p. 172.) 
a, Apothecia brightly coloured. (Callopis- @ 
mella Wedd. Mém. Soc. Cherb. t. xix. p. 276.) 
27. L. citrina Ach. Lich. Univ. (1810) 
p. 402; Nyl. Bull. Soc. Bot. Fr. t. xiii. p. 366. Fig. 63. 
—tThallus effuse, granuloso-leprose, rimoso-sub- — Lecanoracerina Ach. 
areolate, citrine (K+ purplish). Apothecia —a, A spore, X 
_ 850. 0b, Jointed 
moderate, plane or somewhat convex, orange ecuniia: and 
yellow (K + purple); the thalline margin thin, epermatia, x 500. 
entire, at length obliterated ; spores ellipsoid, 
polari-bilocular, colourless, 0,010-15 mm. long, 0,005-8 mm: thick. 
—Sm. Eng. Bot. ii. p. 192; Tayl. in Mack. Fl. Hib. ii. p. 138; 
Cromb. Grevillea, xii. p. 61.—Placodium citrinum Leight. Lich. 
Fl. p. 177, ed. 3, p. 163. P. murorum subsp. citrinum Cromb. 
Lich. Brit. p. 45; var. e. citrinum Mudd, Man. p. 1382. Lichen 
citrinus Eng. Bot. t. 1793 (three lower figs.). Verrucaria citrina 
Hoffm. Deutsch. FI. ii. (1795) p. 198 pro parte. Lichen candelarius 
Huds. Fl. Angl. p. 444 pro parte; With. Arr. ed. 3, iv. p. 27 pro 
parte. Lichenoides crustosum, orbiculis et scutellis flavis Dill. Muse. 
136, t. 18, f. 18 B—Brit. Evs.: Leight. n. 86; Larb. Lich. Hb. 
n. 86. 
Differs at once from Z. (Placodium) murorum, of which it has fre- 
quently been regarded as a variety, in not being radiate at the circum- 
ference, while connecting states are never found. The thallus occasionally 
spreads extensively, varying somewhat in thickness, at times subevane- 
scent, and is often of a greenish-yellow colour when growing in shady 
places, and in old plants is partially more or less greyish-citrine. The 
apothecia when present (for the eo is often sterile) are generally 
numerous, at first somewhat innate, becoming at length convex, with the 
thalline margin excluded. 
Hab. On the mortar of walls, rarely on rocks, very rarely on old 
trunks of trees, chiefly about towns and villages, in aes lowland, 
B 
