74 LECANO-LECIDKKI [lECIDKA 



In the two British specimens, whicli are well fertile, the thallus is 

 almost obsolete. It might readily be taken for an ecrustaceous state 

 of L. lapicida, but differs in the thinner spores. Its nearest ally is 

 L. promiscua'Nyl., a, plant of the Pyrenees, where this species also 

 was originally detected. The spermogoncs are not unfrequent with 

 spermatia straight, 0,009-14 mm. long, 0,0005-6 mm. thick. 



Hab. — On a quartzose boulder in a subalpine situation. — B. M. 

 Morrone, Braemar, Aberdeenshire (the only locality). 



125. L. silacea Ach. Meth. p. 48 (1803).— Thallus areolate, 

 the areolae convex, tumid, smooth, bright ferruginous or 

 ochraceous-red (K — ,CaCl— ). Apothecia violet-black, numerous, 

 scattered or crowded, varying in size, closely adnate on or 

 between the areolae, plane or convex with an entire or flexuose 

 margin ; hypothecium dark-brownish, the base of the asci often 

 greenish-blue ; paraphyses distinct, violet-black at the tips ; 

 spores roundish-oblong, rather small, 0,010-11 mm. long, 

 0,005-6 mm. thick. — Leight. Lich. Fl. ed. 3, p. 288. L. lapicida 

 var. silacea Mudd Man. p. 209 (1861) (excl. syn.) ; Cromb. 

 Lich. Brit. p. 70; Leight. Lich. Fl. p. 285? Patellaria 

 silacea Hoffm. PI. Lich. i. p. 89, 1. 19, f. 2 (1790)? 



The tumid convex areolae and the dark hypothecimxi separate this 

 species, as now understood, from the ferruginous -ochraceous forms of 

 L. litliopliila. It is iiiapossible to be sure of the citations from 

 older authors, as their descriptions are often imperfect. L. silacea 

 (Engl. Bot. t. 1118) is probably L. litJiophila f. ocJiracea, under 

 which it has been quoted. 



Hab. On rocks. — Distr. Somewhat rare in mountainous districts. — 

 B. M. Sidlaw Hills and Glen Fender, Perthshire ; Glen Callater, 

 Braemar, Aberdeenshire. 



126. L. tessellata Floerke Deutschl. Lich. 4, p. 5(1819).— 

 Thallus whitish or greyish, tartareous, areolate, the areolae 

 plane or convex (K — ). Apothecia scattered or confluent, sessile, 

 adnate, black, slightly pruinose, plane or subconvex with a thin 

 flexuose margin ; hypothecium colourless ; paraphyses loosely 

 coherent, slightly thickened and brownish-black at the apices ; 

 spores ellipsoid, 0,009-12 mm. long, 0,004-6 mm. thick ; hymenial 

 gelatine blue then sordid, the asci violet-red, with iodine. — 

 Cromb. Lich. Brit. p. 82 ; Leight. Lich. Fl. p. 276 ; ed. 3, p. 279. 

 L. lapicida var. cyanea Ach. Meth. p. 38 (1803). L. spilota Fr. 

 Syst. Orb. Veg. p. 286 (1825); Leight. Lich. Fl. p. 277; ed. 3, 

 p. 279. L. pantosticta var. spilota Ach. Lich. Univ. p. 154 

 (1810)? 



Hab. On alpine rocks, not common. — B. M. Ben Lawers, Perth- 

 shire ; Glen Callater, Braemar, Aberdeenshire. 



127. L. lapicida Ach. Meth. p. 37 (1803) pro parte.— Thallus 

 tartareous, thin, minutely cracked-areolate, the areolae plane, 

 whitish or ash-grey. Apothecia appressed or adnate, plane or 



