342 LICHEN ACEI. [PANNTTLAKIA. 



Tayl. in Mack. Fl. Hib. ii. p. 142. Lichen microphyllus Eng. Bot. 

 t. 2128. Brit. Exs. : Cromb. n. 153. 



Externally subsimilar to P. mtcrophyUa, but differs in the less firm, 

 squarnulose thallus, and more especially in the infuscate hypothecium. 

 It forms a thin or thinnish crust, with the squamules at first plane and 

 adnate on the hypothallus, becoming at length granulose and diffract, the 



Suamules being visible only at the immediate circumference. The 

 allus varies somewhat in colour according to situation, becoming more 

 or less blackish, whence form niyricans Leight. Lich, Fl. ed. 3, p. 153. 

 The apothecia are scattered and occasionally darker in colour, but are 

 seldom present in our specimens. 



Hub. On the trunks of old trees in wooded upland districts. Dist.r. 

 Somewhat local, though plentiful where it occurs in the mountainous 

 tracts of W. Britain and S.W. Ireland. B. M. : Near Lydford, Ilustyn's 

 Wood, and Lyuton, Devonshire; St. Breock, Cornwall; Barmouth, Cwm 

 Bychan, and Harlech, Merionethshire ; Beddgelert, Carnarvonshire ; 

 Island of Anglesea. Kentmere, Westmoreland. New Galloway, Kirk- 

 cudbrightshire ; Inverary, Barcaldine, and Appin, Argyieshire ; Crianla- 

 rich, Loch Katrine, and Glen Lochay, Perthshire ; Craig Cluny, Braemar, 

 Aberdeenshire ; Glen Ach-na-Shilloch, Iloss-shire. Glen Bower W^oods 

 and GlengarifF, co. Cork; Turk Mt. and Dinish, Killarney, co. Kerry. 



Var. /3. incrassata Nyl. ex Lamy, Bull. Soc. Bot. t. xxv. (1878) 

 p. 389. Thallus thick, densely coralloideo-stipate, brownish-black ; 

 hypothallus spongioso-rhizinose. Apothecia very rare, convex, 

 brownish-black. Cromb. Grevillea, xviii. p. 44. Pannaria tripto- 

 phi/lla var. incrassata Nyl. Not. Sallsk. pro F. et Fl. F. Forh. v. 

 (1866) p. 124. Pannaria lasitlla Stirt. Scot. Nat. iv. p. 164. 



Distinguished by the darker, much thicker thallus (4-6 mm. thick), and 

 by the peculiar hypothallus. It has only recently been met with in a 

 fertile condition. 



Hob. On the trunks of old ash trees, rarely on mossy ground among 

 rocks, in upland wooded districts. Distr. Local and scarce in the S.W. 

 Highlands, and among the S. andN. Grampians, Scotland. B. M. : Glen 

 Creran, Barcaldine, Argyieshire (frt.) ; Glen Lochay, Killin, Perth- 

 shire. 



4. P. nigra Nyl. ex Stiz. St. Gall. Nat. Gcs. 1882, p. 336. 

 Thallus subdeterminate, minutely coralloicleo-granuloso-crustaceous, 

 usually diffracto-areolate, thinnish, dark-greyish-black, brownish- 

 black or black ; hypothallus bluish-black. ' Apothecia lecideine, 

 small, plane or slightly convex, black, internally pale-whitish, the 

 margin entire, concolorous ; spores ellipsoid, 1-septate (or simple 

 and oleoso-locular), 0,011-18 mm. long, 0,005-7 mm. thick ; hypo- 

 thecium brownish-black, paraphyses thick ; hymenial gelatine deep- 

 bluish and then dark-violet with iodine. Cromb. Grevillea, xii. 

 p. 58. Pannaria nigra Cromb. Lich. Brit. p. 43 ; Leight. Lich. Fl. 

 p. 168, ed. 3, p. 154. Lecothecium nig rum Mass., Mudd, Man. p. 175 

 pro parte. Collema nigrum Sm. Eng. Fl. v. p. 207 ; Tayl. in Mack. 

 Fl. Hib. ii. p. 107. Placyiiihium nigrum Gray, Nat. Arr. i. p. 395. 

 Lichen niger Huds. Fl. Angl. ii. (1778) p; 524 ; With. Arr. iv. p. 10 ; 

 Eng. Bot. t. 1161. Brit. Kvs. : Leight. n. 366. 



