474 LICHENACEl. [lECANORA. 



carea Miidd. Man. p. 161, t. 3. f. 55. Urceolaria calcarea Sm. Eng. 

 Fl. V. p. 172 ; Tayl. in Mack. Fl. Hib. ii. p. 132; Gray, Nat. Arr. 

 i. p. 459. Lichen calcareus Linn. Sp. PI. (1753) p. 13 40; Huds. 

 Fl. Angl. p. 442; With. Arr. ed. 3, iv, p. 6 pro minima parte. 

 Lichen tessellatus Eng. Bot. t. 553. Urceolaria tessellata Ach., Gray, 

 Nat. Arr. i. p. 4Q0.— Brit. E.rs.: Leight. n. 13; Mudd, n. 133; 

 Larb. Lich. Hb. n. IGG. 



Easily rncognized among British species by the whitish or chalky- 

 "white thallus. In its more typical condition it is a. co7icreta (Schaer. 

 Spicil. p. 73) Leight. Lich. Fl. ed. 3, p. 192 {tessellata, Ach.), with the 

 tballus determinate, often bubetfignrate at the circumference, and the 

 areolae contiguous, anuulose. The apotbecia are numerous, often crowded, 

 at times naked, with the proper margin at leugth discrete from the 

 thalline margin. The spermo<!ones are frequent, dark-brown or blackish, 

 with spermatia aciculari-cylindrical, 0,007-9 mm. long, about 0,001 mm. 

 thick. 



Sab. On calcareous rocks and walls, rarely granitic, in maritime and 

 upland districts. — Distr. General and common in limestone tracts of 

 Great Britain and Ireland ; not seen from the Channel Islands. — B. M. : 

 Burgh Castle, Suffolk; Peasemarsh, Sussex; Plymouth, S. Devon; near 

 Penzance, Cornwall ; Bathampton Downs, Somerset ; Cunning Dale, 

 near Buxton, Derbyshire; Malvern Hills, Worcestershire; Barmouth, 

 Merionethshire; Great Orme's Head, Carnarvon; Island of Anglesea; 

 Bilsdale, Yorkshire; Eglestone and Teesdale, Durham; Levens, West- 

 moreland. Appiu and Island of Lis^more, Argyleshire ; Craiyr Tulloch, 

 Bhiir Athole, Perthshire ; Morrone, Braemar, Aberdeenshire. Duukerron, 

 CO. Kerry ; Maam, Count mara, co. Galway. 



Var. /3. contorta Nyl. Flora, 1872, p. 554. — Thallns effuse, 

 white or greyish-white, the areolae more or less discrete, elevated 

 in the centre, depressed and at times subeffigurate at the circum- 

 ference. Apothecia immersed. ^Leight. Lich. Fl. cd. 3, p. 193. — 

 Aspiciliei calcarea ft. contorta Mudd, Man. p. 162. Urceolana 

 contorta Tayl. in Mack. Fl. Hib. ii. p. 132. Lichen contortnsHo^m. 

 Deutsch. Fl. ii. (1795) p. \m.—Brit. Exs. : Leight. n. 322. 



Distinguished by the form of the discrete or subdiscrete thalline 

 areolae. It usually spreads extensively over the substratum and is well 

 fertile. 



Hah. On calcareous rocks in maritime, but chiefly upland districts. — - 

 Distr. Somewhat local in Great Britain and Ireland. — B. M. : Near 

 Kingskerswell, S. Devon ; Symmond's Yat, Herefordshire ; Ashwood Dale, 

 Derbyshire ; near Oswestry, Shropsjiire ; Great Orme's Head, Carnarvon- 

 shire ; Teesdale, Durham. The Ochils, near Stirling ; Craig Tulloch, 

 Blair Athole, Perthshire ; Craig Guie, Braemar, Aberdeenshire. The 

 O'Donoghue's Prison, KiUaruey, co. Kerry. 



Form monstrosa Cromb. Grevillca, xix. (1891) p. 57. — Thallus 

 effuse, snow-white ; areola) discrete, scattered, rounded, convex, 

 entire at the margins. Apothecia abortive, minute, deeply im- 

 mersed. — Z-. calcarea var. monstrosa Lamy, 13ull. Soc. Bot. t. xxx. 

 (1883) p. 392. 



