476 LICHEXACEI. [lECANOEA. 



and on the S. and Central Grampians, Scotland. — B. il. : Cunswick Scar, 

 Westmoreland. Craior Calliacli, above Loch-na-Gat, Ben Lawers, and 

 Craig Tulloch, Blair Athole, Perthshire. 



1 74. L. poriniformis Xyl. Flora, 1865, p. 353 — Thallus eflfuse, 

 thinnish, fiim. rimoso-difFract, greyish or pale-grey (K -|- yello^v). 

 Apothcoia small, innate in convex, somewhat prominent verrucas, 

 pertusarioid, pale or brownish ; the epithecium pale, punctiformi- 

 contracted ; spores 6-8nas, ellipsoid, 0,070- SO mm. long, 0,034-50 

 mm. thick ; paraphyses slender ; hymenial gelatine bluish, then 

 tawny-yellow with iodine. — Carroll, Journ. Bot. 1866, p. 23 ; 

 Cromb. Lich. Brit. p. 56; Leight. Lieh. El, p. 190, ed. 3, p. 203. — 

 Brit. Exs. : Cromb. n, 74. 



Looks exactly like a Pertusaria, allied to P. xanthostoma Somm. 

 The characters, however, of the hymenium, of the thecte (which are 

 fiigaciousj, and of the spores show that it is a Leccawra distantly related 

 to the preceding species. The thallus spreads somewhat extensively 

 Avith the fertile verructe scattered or approximate. Usually there is but 

 a single apothecium in each verruca, though not uufrequently tliere are 3 

 or 4, when the verrucas are rather larger. 



Hab. On schistose rocks and walls, rarely iucrustiug mosses, or on 

 trunks of old firs, in maritime and subalpine districts. — Distr. Local and 

 scarce among the S. and Centi'al Grampians and on the X.E. coast of 

 Scotland. — B. ]Ni,: Ben Lawers and Craig TuUoch, Perthshire; near 

 Portletheu, Kincai-dineshii-e. 



175. L. Dicksonii Xyl. ex Carroll, Journ. Bot. (1867) p. 255. — 

 Thallus determinate, thin, smooth, rimose or areolato-rimose, 

 ochraceo-ferruginous, opaque (K — , CaCl — ); hypothallus thin, 

 black, limiting the thallus. Apothecia leeideine, small, innate, 

 concave, black, internally blackish (greyish in the centre), the 

 proper margin thick, black ; spores Snce, ellipsoid, 0,011-14 mm. 

 long, 0,006-8 mm. thick ; hypothecium brownish-black ; paraphyses 

 not discrete, fuliginous towards the apices ; hymenial gelatine 

 bluish, then wine-red with iodine. — Cromb. Lieh. Brit. p. 55 ; 

 Leight. Lich. Fl. p. 211, ed. 3, p. 196. — Lichen Diclsonii Ach. 

 Prodr. (1798) p. 76, Lecidea melanoj^haxi Fr., Mudd, Man. p. 206. 

 Lecidea (Edcri (non Web.) Tayl. in Mack. Fl. Hib. ii. p. 122 ; Sm. 

 Eng. El. V. p. 178 ; Hook. El. Scot. ii. p. 38 ; Gray, Nat. Arr. 

 i. p. 466. Lichen CEderi Eng. Bot. t. 1117; With. Arr. ed. 3, iv. 

 p. 11 pro parte. — Brit. Exs.: Leight. n. 127 ; Cromb. n. 72. 



By many authors regarded as a Lecidea, with much the aspect of 

 L. (Edcri, with which it has been confounded ; but its most approjniate 

 place is in this section. The peculiar colour of tlie thallus, as in various 

 other instances, is owing to sutfusion with peroxide of iron. Typically, 

 according to specimens from Kerguelen Land, it is greyish {vide Linn. 

 Soc. Journ. Bot. xv. p. 190 s. n. Lecidea siucerida Xyl.). The apothecia 

 are numerous and at times somewhat crowded. 



Hab. On rocks and walls, chiefly schistose, in mountainous regions. — 

 Distr. Somewhat local, though usually plentiful in Great Britain and in 



