LKCANOKA.] LECANO-LECIDEEI. 475 



Only a well-marked form of this variety, characterized by the isolated 

 areoL-e, in each of which there is a central umbilicus indicating the 

 abortive apothecia. Probably it may be only a very young condition. 



Hab. On calcareous stones of a wall in an upland situation. Distr. 

 Only very sparingly among the Central Grampians, Scotland. B. M. : 

 Glen Fender, Blair Athole, Perthshire. 



Var. y. Hoffmann! Somm. Suppl. Fl. Lapp. (1826) p. 102. 

 Thallus thinnish or thick, contiguous or subcontiguous, glaucescent. 

 Apothecia elevated, moderate or somewhat large, the margin often 

 rugoso-crenate ; spores 0,021-34 mm. long, 0,0 1 6-18 mm. thick. 

 Cromb. Grevillea, xix. p. 57 ; Lich. Brit, p. 54 pro parte ; forma 

 Hoffmanni Leight. Lich. Fl. p. 209 pro parte, ed. 3, p. 193. 

 Urcfolaria Hoffmanni Gray, Nat. Arr. i. p. 459 pro parte. Lichen 

 Hoffmanni Ach. Prodr. (1798) p. 31 ; Engl. Bot. t. 1940. Brit. 

 Exs. : Mudd, n. 134. 



A very distinct variety, if not a subspecies, having much the general 

 aspect of L. gibbosa, but belonging to L. calcarea, as shown by the 

 spernmtia, which in form and size are identical. From var. /3, with 

 which it has often been confused, it differs in the more contiguous and 

 differently coloured (at times subpluuibeous) thallus and the less immersed 

 apothecia. 



Hab. On rocks and walls (not exclusively calcareous) in maritime, but 

 chiefly in hilly districts. Distr. Only here 'and there in Great Britain ; 

 apparently rare in N.W. Ireland. B. M. : Beachy Head, Sussex; near 

 Cirencester, Gloucestershire ; Buxton, Derbyshire ; Chance's Pitch, Mal- 

 vern, Worcestershire ; near Roseberry, Cleveland, Yorkshire ; Levens, 

 Westmoreland. Ben Cruachan, Argyleshire ; Glen Fender, Blair Athole, 

 Perthshire ; Portlethen, Kincardinesfiire. Doughruagh mts., Connemara, 

 co. Galway. 



173. L. verrucosa Nyl. Mem. Soc. Cherb. t. v. (1857) p. 113; 

 Lich. Scand. p. 156. Thallus effuse, vermcoso-unequal, naked or 

 slightly pulverulent, white or glaucous-white (K , Ca Cl ). Apo- 

 thecia immersed in the verrucoe, moderate, concave, at length 

 somewhat plane, blackish, naked or pruinose, the thalline margin 

 thick, entire, inflexed ; spores subellipsoid, large, 0,030-62 mm. 

 long, 0,016-32 mm. thick; paraph j-ses not discrete; hymenial 

 gelatine pale-bluish, then sordid-yellow or wine-red with iodine. 

 Cromb. Lich. Brit. p. 55 ; Leight. Lich. Fl. p. 214, ed. 3, p. 200. 

 Aspidlia verrucosa Mudd, Man. p. 164. Urceolaria verrucosa Ach. 

 Lich. Univ. (1810) p. 339 Brit. Exs. : Cromb. n. 73. 



Characterized by the white, usually more or less farinose thallus, by its 

 place of growth, and by the large spores. The thallus varies somewhat 

 in thickness and colour according to the habitat, while on more sterile 

 soil it is smaller and determinate. The apothecia are numerous, at first 

 urceolate, then plane, the thalline margin rarely obsolete, when the 

 proper margin, which is thin and blackish, becomes conspicuous. 



Hab. Incrusting mosses on rocks, rarely on the ground (chiefly cal- 

 careous), in upland andsubalpine situations. Distr. Local in N. England 



