470 LICHENACEI. [LECANOEA. 



and occasionally bears pale-reddish cephalodia similar to those of Lecidea 

 panceola. When growing iu wet places by streams it is more expanded, 

 of a livid-grey colour, uon-cephalodiiferous, with the thalline margin 

 of the apotheeia usually obliterated (form rivularis, Cromb.). The 

 apothecia are somewhat scattered, innate or at length nearly superficial, 

 with the disc free at the circumference. 



Hal. On micaceo-schistose rocks in alpine places. Distr. Only very 

 sparingly near the summits of two of the S. Grampians, Scotland. 

 B. M. : Ben Lawers and Craig Calliach, Perthshire. 



169. L. gibbosa Nyl. Not. Siillsk. pro F. et Fl. Fenn. Forh. n. s. 

 v. (1866) p. 137. Thallus determinate, thick, areolato-verrucose 

 or gibbous, greyish, dark-grey or dark-greenish-brown (K , 

 CaCl , medulla I); hypothallus black, limiting the thallus. 

 Apothecia at first immersed and concave, then emersed and plane, 

 submoderate, black, naked ; the thalline margin entire or slightly 

 crenulate, persistent ; spores 6-8nso, rarely 4na\ ellipsoid or sub- 

 globose, large, 0,021-38 mm. long, 0,012-24 mm. thick ; paraphyses 

 not discrete ; hymenial gelatine pale-bluish, then tawny or sordid- 

 wiue-red with iodine. Leigh t, Lich. Fl. ed. 3, p. 193, ed. l,p. 209 

 pro parte ; Cromb. Lich. Brit. p. 55 pro parte. Aspieilia gibbosa 

 Mudd, Man. p. 162. Urceolaria gibbosa Sm. Eng. Fl. v. p. 172 ; 

 Gray, Nat. Arr. i. p. 458. Lichen gibbosus Ach. Prodr. (1 798) p. 30. 

 Lichen gibbosus Dicks. Crypt, fasc. ii. (1790) p. 20, t. vi. f. 5 ; With. 

 Arr. ed. 3, p. 20, from the diagnosis and locality cited is evidently 

 not this species. Brit.Exs.: Leight. n. 175; Cromb. n. 167; Larb. 

 Lich. Hb. n. 220. 



A very variable plant presenting the varieties and subspecies that 

 follow: while several states of the type itself were by older authors 

 regarded as distinct species. In a young condition, especially when 

 silicicolous, the predominating hypothallus, black and radiately sub- 

 plumose, is everywhere visible, the thalline verrucae being more or less 

 scattered. It is then Lichen fbrosus Eng. Bot. t. 1739 ; Urceolaria 

 yibbosa var. /3. fimbriata Ach., Gray Nat. Arr. i. p. 458. The same with 

 the verrucas here and there greeiiish-sorediiferous, owing no doubt to 

 habitat (moist flints), is Lecanora aspersa Borr. Eiig. Bot. Suppl. t. 2728 ; 

 Sm. Eng. Fl. v. p. 188. Another state, in which the thalline verrucae are 

 subglobular and often discrete, is Lichen tuberculosus Eng. Bot. t. 1733 ; 

 Itinodina tuberculosa Gray Nat. Arr. i. p. 452 ; Lecanora tuberculosa Sm. 

 Eng. Fl. y. p. 188. Occasionally the thalline margin of the young 

 apothecia is coarctate or subcrenulate, whence forma porinoidea (Flot. 

 Lich. Siles. i. p. 128) Leight. Lich. Fl. ed. 3, p. 194. All of these, how- 

 ever, where the plant is very abundant (as in the Kentish locality), 

 often pass into and are mixed up with each other in the same specimen. 

 The spermogones, especially in younger states of the plant, are very 

 frequent, with spermatia 0,009-0,012 mm. long, scarcely 0,001 mm. thick 

 (fide Nyl. Lich. Pyr. Or. Obs. nov. p. 59). 



Hob. On rocks and stones (chiefly flints) in maritime and hilly 

 districts. Distr. Local, though plentiful, in S., W., andN. England ; rare 

 in Wales and in the S.W. Highlands of Scotland: not seen from Ireland 

 nor the Channel Islands. B. M. : Hyde, Isle of Wight; Lydd Beach, 

 Kent j Lewes, S. Downs, St. Leonard's, and Beachy Head, Sussex j 



