ehizocaepon] leoidbace^ 191 



spores broadly fusiform-oblong, very dark-coloured, sometimes 

 halonate, 3-septate, frequently with, longitudinal or oblique septa, 

 0,024-40 mm. long, 0,011-18 mm. thick ; hymenial gelatine deep- 

 blue with iodine. — Mudd Man. p. 221, t. 4, fig. 83 pro parte. 

 Lichenoides nigro-flavum, tabulse geographicse instar pietum Dill. 

 Hist. Muse. p. 126, t. 18, f. 5 (1740). Lichen geographicus 

 L. Sp. PI p. 1607 (1753) ; Huds. PI. Angl. p. 442 ; Lightf. 

 PI. Scot. ii. p. 801; Engl. Bot. t. 245; With. Arr. ed. 3, 

 iv. p. 12 (1796). Lecidea geographica Schser. Spioil. p. 124 (1823) 

 & Enum. p. 105, t. 5, f . 3 ; Hook, in Sm. Engl. PI. v. p. 178 

 pro parte; Tayl. in Mackay PI. Hib. ii. p. 121; Oromb. Lich. 

 Brit. p. 93 ; Leight. Lich. PI. p. 346 ; ed. 3, p. 372 pro parte. 

 L. atrovirens var. geographica Hook. PI. Scot. ii. p. 37 (1821) ; 

 S. P. Gray Nat. Arr. i. p. 465. 



Exsicc. Leight. nos.' 128, 129, 306; Mudd n. 196; Larb. 

 Lich. Hb. n. 352 (f. contigua). 



A variable plant both as to thallus and apothecia. In its more 

 typical and developed state, the thallus, which often spreads exten- 

 sively, is limited and usually intersected by the black hypothallus, so 

 that, as Dillenius says, " it is divided, as it were, into compartments 

 like a map," whence its specific name. When the thallus is con- 

 tiguous at the circumference, it is var. contigua (Mudd I. c. ; Lecidea 

 geographica var. contigua Fr. Lich. Eur. p. 327 (1831) ; f. contigua 

 Leight. Lich. PI. ed. 3, p. 373). The numerous apothecia situated 

 either on or between the areolse are at times more or less confluent, 

 the margin usually very thin is occasionally more developed, becoming 

 tumid and prominent (var. urceolatum Mudd I. c. ; Lecidea geo- 

 graphica var. urceolata Schser. Enum. p. 106 (1850) ; f. urceolata 

 Leight. I. c. p. 374). 



Hah. On rocks and boulders, granitic, schistose, quartzose and 

 arenaceous, from maritime to alpine situations. — Distr. General and 

 abundant in most parts of Great Britain, where it attains the summits 

 of the highest mountains ; not uncommon in the Channel Islands ; 

 apparently rarer in Ireland. — B. M. La Moye, Jersey ; Islands of 

 Guernsey and Alderney ; Pentire, St. Minver, Temple Moor and 

 Lamynack Cliff, near Penzance, Cornwall ; Dartmoor, Devon ; near 

 Bichard's Lock, lilting, Essex ; Bardon Hill and Charnwood Forest, 

 Leicestershire ; Malvern Hill, Worcestershire ; Cader Idris, Aber- 

 dovey, Barmouth and Corwen, Merioneth ; Glyder and Capel Curig, 

 Carnarvonshire (f . urceolatum) ; Hafod, Cardiganshire ; Longmynd, 

 Wrekin Hill, Caer Caradoc and Pontesford Hill, Shropshire ; Bat- 

 tersby Moor (f. urceolatum), Kildale Moor and Lounsdale, Cleveland, 

 Yorkshire ; Teesdale, Durham ; Lamplugh, Cumberland, The Cheviots, 

 Northumberland ; near Loch Skene, Moffatdale, Dumfriesshire ; 

 Arthur's Seat, Edinburgh ; Glen Creran, Argyll ; Sidlaw Hills, 

 Forfarshire ; Craig Calliach, Ben Lawers and Birnam Hill, Dunkeld, 

 Perthshire ; near Portlethen, Kincardineshire ; Morrone, Braemar, 

 and Huntly, Aberdeenshire ; Ben Nevis, Invernessshire ; CuchuUin 

 Hills, I. of Skye ; near Loch Shin, Sutherland ; Keim-an-Eigh, 

 Cork ; Killamey, Kerry. 



Var. atrovirens Koerb. Syst. Lich. Germ. p. 263 (1855). — 

 Thalline areolae smaller, more or less scattered and somewhat 



