a | ae 
224 CYCLOCARPINE [PLACODIUM 
Bedfordshire ; near Cirencester, Gloucestershire ; near Worcester and 
North Malvern, Worcestershire; Wimpole Park and Madingley, | 
Cambridgeshire; Twycross, Leicestershire ; near Masham, Yorkshire ; 
Levens Bridge, Westmoreland; Meldon Park, Wansbeck Valley, 
Northumberland ; Doune Castle, Stirlingshire; Pitfour, Aberdeen- 
shire; Rostellan, Cork ; Innisfallen, Killarney, Kerry ; Castle Connell, 
Limerick. 
Form rupestre A. L. Sm.—Thallus whitish, greyish or obsolete, 
senerally in scattered granules. Apothecia minute, scattered or 
crowded.—Lecidea ulmicola Tayl. in Mackay Fl. Hib. ii. p. 129 
(1836). Lecanora cerina subsp. pyracea f. rupestris Nyl. Lich. 
Seand. p. 145 (1861). ZL. luteoalba f. rupestris Cromb. Monogr. 
i. p. 386 (1894). 
Ezsice. Johns. n. 313; Leight. n. 213; Mudd n. 146. 
The structure of the apothecium, spores, etc., is similar to that of 
the species; it differs chiefly in the habitat which has influenced the 
appearance of the thallus. It is synonymous with f. caleicola Arn. 
Hab. On limestone, mortar or arenaceous stones mostly in 
upland districts.—Distr. Rare in 8. and N. England and 8.W. Ireland. 
—B. M. Newton Abbot, Devon; Ingleby, Cleveland, Yorkshire ; 
Bolam, Durham; Dunkerron, Kerry. 
39. Pl. rupestre Branth & Rostr. in Bot. Tidskr, iii. p, 206 
(1869).—Thallus thin, determinate, cracked-areolate, dirty-whitish 
or -greyish (K —). Apothecia adnate, small or moderate in size, 
plane or convex, not marginate, yellowish- or dull-red (K + purple) ; 
paraphyses slender, swollen and septate at the tips, conglutinate ; 
spores ellipsoid or ovoid, simple, 9-15 pw long, 5-8 p thick.— 
Lichen rupestris Scop. Fl. Carn. ed. 2, ii. p. 363 (1772); Engl. 
Bot. t. 2245. L. viridiflavescens Wulf. in Jacq. Coll. iii. p. 101, 
t. 2, fig. 1 (1789). Verrucaria rufescens Hoffm. Pl. Lich. i. p. 80, 
t. 17, fig. 1 (1790). Lecidea rupestris vary irrubata Ach. Lich. 
Univ. p. 206 (1810); var. viridiflavescens Mudd Man. p. 194 
(1861). LZ. irrubata Ach. Syn. Lich. p. 40 (1814); Hook. in 
Sm. Engl. Fl. v. p. 183; Tayl. in Mackay Fl. Hib. ii. p, 128. 
Lecanora calva var. irrubata Cromb. Lich. Brit. p. 47 (1870). 
L. rupestris Leight. Lich. Fl. p. 190 (1871) (incl. f. rufescens and 
f. viridiflavescens) ; ed. 3, p. 204. L. irrubata Nyl. ex Norrl. 
in Medd. Siillsk. Faun. & Fl. Fenn. i. p. 22 (1876); Cromb. 
Monogr. i. p. 387. 
Exsicc. Johns, nos. 194, 268 (2), 410; Larb. Lich. Hb. n. 100; 
Leight. n. 119; Mudd n. 161. 
Generally classified under Lecidea Sect. Biatora, on account of the 
simple spores, but belongs to Placodium (Sect. Blastenia), not only 
on account of the spermogones, which have septate sterigmata and 
pleurogenous spermatia, but also the presence of parietin, the lichen 
acid which is present only in lichens of this order. It can easily be 
recognized and placed by the reaction with potash. The apothecia 
becomes a darker red with age (f. »wfescens), and the spores have 
generally thickened walls, though rarely any indication of central 
