14 LECANO-LECIDEEI [lECIDEA 



sparingly present, are in their young state plane and margined, the 

 margin speedily becoming obsolete. 



Hah. On peaty ground in mountainous regions. — Diatr. Only| a 

 few localities in N.W. England, the S. and Central Grampians, 

 Scotland, S.W. and N.E. Ireland. — B. M. Mardale, Westmoreland ; 

 Glen Ealloch and Uannoch, Perthshire ; near Ballintoy, Antrim. 



7. L. Friesii Ach. in Liljebl. Sv. Fl. p. 610 (1816).— Thallus 

 effuse, squamulose, granulose, cervine or cervine-yellow (K — , 

 CaCl — ), the squamules small, rotundate, inflexed, convex- 

 gibbose, at times plicate, smooth and shining. Apothecia small, 

 sessile, black, naked, plicate-crispate, the margin thin, persistent ; 

 paraphyses concrete, hypothecium dark-brown ; spores ellipsoid, 

 0,007-8 mm. long, 0,003-4 mm. thick ; hymenial gelatine pale- 

 bluish with iodine. — Leight. in Ann. Mag. Nat. Hist. xiv. p. 404, 

 t. ix. f. 8, 9, 11 (1864) & Lich. Fl. p. 253 ; ed. 3, p. 245 ; Cromb. 

 Lich. Brit. p. 92. Psora caradocensis Mudd Man. p. 169 pro 

 parte, t. 3. f. 61 (1861). 



Exsicc. Mudd n. 142. 



Somewhat similar to and at first sight apt to be taken for Bilimbia 

 caradocensis, but distinguished by its thallus and spores. The 

 British plants seen are only sparingly fertile ; the spermogones, 

 rarely present, are verrucaeform, black, scattered or conglomerate, 

 with spermatia oblong or subcylindrical, straight, about 0,003 mm. 

 long. 



Hah. On decorticated trunks of oak and old palings, in an upland 

 district. — Distr. Very local in N. England, but probably to be detected 

 elsewhere. — B. M. Boysdale, Cleveland and Farndale, Yorkshire. 



8. L. OStreata Scheer. Spicil. p. 110 (1828).— Thallus effuse, 

 squamulose, glaucous or pale-olive (K — , CaCl + dark-crimson), 

 the squamules imbricate, reniform, crowded or scattered, ascending 

 or suberect smooth, crenate, the under side and margins usually 

 white-pulverulent. Apothecia moderate, scattered, basal on the 

 squamules, black, slightly glaucous-pruinose, the margin thin, at 

 length flexuose ; hypothecium thick, brownish-black ; paraphyses 

 concrete, colourless, yellowish in the mass ; spores 8nate, ellipsoid 

 or fusiform, simple, small, 0,010-12 mm. long, 0,0025-35 mm. 

 thick ; hymenial gelatine bluish with iodine. — Cromb. Lich. Brit. 

 p. 91 ; Leight. Lich. Fl. p. 253 ; ed. 3, p. 245. Psora ostreata 

 Hoffm. Deutschl. Flora (1795 ii. p. 163) ; Mudd Man. p. 169. 

 P. scalaris Hook, in Sm. Engl. Fl. v. p. 192 (1833). Lichen 

 scalaris Sm. Engl. Bot. t. 1501 (1805). Lepidoma scalare 

 S. F. Gray Nat. Arr. i. p. 461 (1821). 



Exsicc. Leight. n. 50 ; Mudd n. 141 ; Cromb. n. 188. 



When sterile might readily be taken for var. ostreata of Cladonia 

 macilenta (as noticed in Part I. p. 171), but is at once distinguished 

 from this by the different chemical reaction of the thallus. It spreads 

 extensively over the substratum, the squamules being either plane or 

 slightly convex. The apothecia in this country are apparently 

 extremely rare and occur on only a few of our specimens. 



