PLACODIUM | PHYSIACEX 225 
septation. Johnson’s Hrsicc. n. 268, seems to belong here, but our 
specimen is imperfectly developed. 
Hab. On calcareous rocks, mortar, sandstones, etc., in maritime 
and inland localities—Distr. Not uncommon throughout Great 
Britain and Ireland.—B. M. Near Penzance, Cornwall; Anstey’s 
Cove, Torquay and Cornworthy, Devon; Beachy Head, Duncton and 
Beeding Downs, Sussex; Shiere, Surrey; Windsor Great Park, 
Berks; Bathampton Downs, Somerset; Norton, near Worcester ; 
Llanymynech and Whitcliff Rocks, near Ludlow, Shropshire ; 
Bilsdale and near Carlton, Cleveland, Yorkshire; Beamish, Durham ; 
Leven’s Park, Westmoreland; Chollerford, Northumberland ; Appin, 
Argyll; Craig Tulloch, Perthshire ; Kirkland, Fife; Killarney, Kerry ; 
Ben Bulben, Sligo; near Kylemore, Connemara, Galway; Mallaranny, 
Achill Sound and Clare Island, Mayo. 
Var. calvum A. L. Sm.—Thallus effuse or determinate, 
thickish or immersed in the stone, whitish. Apothecia small 
or moderate in size, subimmersed in the thallus or in the rock, 
reddish-yellow (K + purple); paraphyses thickish.—Lichen calvus 
Dicks. Pl. Crypt. fasc. ii. p. 18, t. 6, fig. 4 (1790); With. Arr. 
ed. 3, iv. p. 14; Engl. Bot. t. 948. Lecidea rupestris Ach. Lich. 
Univ. p. 206 (1810); S. F. Gray Nat. Arr. i. p. 472; Hook. FI. 
Scot. ii. p. 39 & in Sm. Engl. Fl. v. p. 183; Tayl. in Mackay 
Fl. Hib. ii. p. 128; Mudd Man. p. 193. Lecanora calva Nyl. 
Lich. Seand. p. 147 (1861); Cromb. Lich. Brit. p.47. Lecanora 
rupestris £. calva Leight. Lich. Fl. p. 191; ed. 3, p. 203; Cromb. 
in Grevillea xii. p. 58. Lecanora irrubata subsp. calva Lamy 
in Bull. Soc. Bot. Fr. xxx. p. 378 (1883); Cromb. Monogr. 
1. p. 387. 
Exsicc. Bohl. n. 73 (drawing only) ; Johns. n. 195. 
Differs from the species in the thallus, which is not areolate, and 
in the apothecia immersed at the base and leaving pits in the rock 
(foveolate). They are generally larger than in the species. 
Hab. On calcareous rocks, rarely on flints in maritime and 
mountainous districts.—Disty. More restricted than the species 
though common where it occurs in Great Britain, not seen from 
Ireland.—B. M. I. of Wight; Peasemarsh, near Lewes and Beeding 
Downs, Sussex; Lydd Beach, Kent; Reigate, Surrey; Compton 
Bishop, Somerset; Craig-y-Rhiw, Oswestry, Shropshire; Llangollen, 
Denbighshire ; Anglesea; Egglestone, Durham ; Leven’s Park, West- 
moreland; Bywell, Northumberland; King’s Park, Edinburgh; 
Achosragan Hill, Appin and near Ben Cruachan, Argyll; Craig 
Tulloch, Perthshire ; Craig Guie and Morrone, Braemar, Aberdeenshire. 
Form incrustans A. L. Sm.—Thallus thin, white, mostly 
immersed in the rock. Apothecia small, plane or slightly convex, 
immersed.—Patellaria incrustans DC, Fl. Fr. ii. p. 361 (1805). 
Lecidea rupestris var. incrustans Scher. Lich. Helv. Spicil. p. 184 
(1833); Mudd Man. p. 194. Lecanora rupestris f. incrustans 
Leight. Lich. Fl. p. 191 (1871); ed. 3, p. 203. ZL. irrubata 
subsp. calva f. incrustans Cromb. in Greyillea xviii. p. 46 (1889) 
& Monogr. i. p. 388. 
I. 
Q 
