btatorina] lecideace^ 123 



Scarcely to be distinguished from the species, the minor differ- 

 •ences being due to the nature of the substratum. In the specimens 

 seen the apothecia are numerous. 



Hah. On schistose rocks in hilly and mountainous districts. — 

 Distr. Very local and scarce in S.W. England, N. Wales, and the 

 central Grampians, Scotland. — B. M. Bathampton Downs, Somerset ; 

 •Cader Idris, Merioneth ; Craig Tulloch, Blair Athole, Perthshire. 



23. B. premnea A. L. Sm. — Thallus greyish-green or whitish, 

 cartilaginous, thin, unequal, continuous or rimose(K — , CaCl — ). 

 A.pothecia rather large, black, scattered, sessile, plane, the disc 

 minutely papillate, margin thickish, shining, becoming convex 

 ^nd immarginate ; hypothecium bluish-black ; paraphyses slender, 

 •conglutinate, dark-bluish-green or dark-brown towards the tips ; 

 spores ellipsoid or oblong, obtuse, rather large, 0,020-30 mm. 

 long, 0,008-18 mm. thick, sometimes slightly constricted at the 

 septum ; hymenial gelatine blue then wine-red with iodine. — 

 B. grossa Mudd Man. p. 181 (1861). Lecidea premnea Fr. in 

 Vet. Acad. Handl. 1822, p. 260 (pro max. parte, fide Th. Fr. 

 Lich. Scand. p. 581) (non Ach.). L. grossa Nyl. in Act. Soc. 

 Linn. Bord. ser. 3, i. p. 385 (1857); Cromb. Lich. Brit. p. 89 ; 

 Leight. Lich. Fl. p. 310; ed. 3, p. 328. L. leucoplaca Chev. Fl. 

 Env. Paris, p. 572 (1826). 



Exsicc. Mudd n. 147 ; Leight. n. 125 (as Lecidea leucoplaca) ; 

 Johns, n. 360. 



Liable to be confused with Lecanactis pi-emnea, to which it is 

 ■externally somewhat similar. Often cited as L. grossa Pers. a 

 manuscript name in Hb. Mougeot. 



Hah. On trunks of trees in wooded regions. — Distr. Frequent in 

 most parts of the British Isles. — B. M. Withiel, Cornwall ; Newton 

 Bushell, Devon ; Bembridge, I. of Wight ; Lyndhurst, Hants ; 

 between Heniield and Brighton, and Cowdown, Poynings, Sussex ; 

 Shiere, Surrey ; Kent ; Chedworth Woods, near Cirencester, 

 Gloucestershire ; Gopsall Wood, Leicestershire ; Nannau, Dolgelly, 

 Merioneth ; Windermere, Westmoreland ; Airyliolme Wood, Cleve- 

 land, Yorkshire ; Lanark ; near Edinburgh ; The Trossachs, Kenmore, 

 Aberfeldy, Glen Falloch, Glen Lochay and Finlarig, Killin, Perthshire ; 

 Appin and Barcaldine, Argyll ; Invermoriston and Fort William, 

 Invernessshire ; Morrone, Braemar, Aberdeenshire ; Derryquin, 

 Glencar, Muckruss and Dinish, Kerry; Dromoland, Clare; Loughcooter, 

 Gal way. 



24. B. pulverea Mudd Man. p. 180 (1861).— Thallus effuse, 

 thickish, minutely granular-pulverulent or leprose, soft, greyish- 

 green, glaucous, or yellowish-green, becoming white (K + yellow, 

 CaCl — ). Apothecia somewhat large, scattered, adnate-sessile, 

 plane, black with a paler rather prominent margin, becoming 

 convex and immarginate, pale within, the lower stratum white ; 

 paraphyses coherent, blackish at the apices ; spores oblong or 

 ellipsoid, 1-septate, 0,015-19 mm. long, 0,007-9 mm. thick ; 

 hymenial gelatine deep-blue then violet-coloured with iodine. — 



