466 LICHEXACEI. [lECANOKA. 



A very distinct plant, -wliich when less developed and sterile entirely 

 resembles isidinid states of a Pertusaria, in wliich genus it has been 

 placed by Th. M. Fries (Lich. Scand. p. 307) and to which probably it 

 really belongs. The peculiar p ipillae are corallinoid, fragile, more or less 

 branched, at first short, then somewhat elongate, often bearing at the 

 apices dark brown ven-ucse, which were mistaken for the fructiHcation by 

 some older authors. In our Islands it is r;irely well fertile. The spermo- 

 gones, however, are not unfrequent, with sp'^rmatia (fide Nyl.) 0,0035 

 mm. long, 0,0005 mm. thick. 



Hab. On mosses upon the ground, rarely on schistose rocks in alpine 

 situations. — Distr. Local and scarce towards the summits of a few of the 

 higher mts. of the S. and N. Grampians, Scotland. — B. M. : Craig 

 Oalhach and H^n Lawers, Perthshire ; Caii-ngorm and Cairntoiil, 

 Braemar, Aberdeenshire. 



Form depressa Cromb. — ■ Thallus epapillate, greyish-white. 

 Apothecia minute, adnate, numerous and crowded. 



Perhaps only a stunted condition depending on situation, as a few very 

 short, simple papillre are here and there visible. 



Hab. On the bare ground in an alpine locality. — Distr. Very sparingly 

 on one of the X. Grampians, Scotland.— B. M. : Summit of Ben-naboord, 

 Braemar, Aberdeenshire. 



163. L. cinerea Somm. Suppl. Fl. Lapp. (1826) p. 99 ; Xvl. Not. 

 Siillsk. pro F. et Fl. Fenn. F.irh. n. ser. v. (1866) p. 136.— Thallus 

 determinate or subefFuse, rimoso-areolate or diffracio-areolate, grey 

 or greyish-white (K 4- yellow, then rusty-red, CaCl — , medulla 

 I — ) ; hypothallus black. Apothecia small or submoderate, im- 

 mersed and concave, at length sessile and plane, black, naked ; the 

 thalline margin entire, subpersistent : spores 8me (rarely 6na?), 

 subellipsoid, 0,015-23 mm. long, 0,008-14 mm. thick : paraphyses 

 not discrete; hymenial gelatine bluish, then tawny or wine-red 

 with iodine. — Cromb. Lich. Brit. p. 54 ; Leight. Lich. Fl. 

 p. 195, ed. 3, p. 172. — As].yicilia cinerea Mudd, ^Maii. p. 162 ])ro 

 parte. UrceoJana cinerea 8m. Eng. Fl. v. p. 172 ; Tayl. in Mack. 

 Fl. Hib. ii. p. 132 ; Gray, Xat. Arr. i. p. 458. Lichen cinereus 

 Ach. Prodr. (1798) p. 32; Eng. Bot. t. 1751.— As observed by 

 Acharius I. c. this is scarcely Lirlun cinereus Linn. Mant. i. (1767) 

 p. 132, of which there is no specimen in his Herbarium ; nor is it 

 Lichen cinereus Huds. Fl. Angl. ed. 2, p. 525. 



A good species, though often not well characterized nor rightly 

 limited. In this latter respect various others liave been subsumed under 

 it which are now readily separated, apart from the other distinctive 

 characters, by their negative reactions Avith K. It is thus a nnich less 

 variable plant than was supposed, and is not so apt to be confused with 

 some of its allies. The thallus,which is generally well fertile, occasionally 

 spreads extensively, but is usually limited by the hypothallus. ,\ state 

 verv rarelv occurs in Britain on schistus.^ rocks (Tremadoc, N. Wales, /iV/e 

 Leighton) in which the thallus is greyish-ochreous, when it is form 

 ochracea Leight. Lich. Fl. ed. 8, p. 19.3 {Urceolaria cinerea y. ochracea 

 Schaer. Spicil. p. 72). The spermogoues are frequent, with spermatia 

 0,010-21 mm. long, scai'cely 0,001 mm. thick. 



