i. p. 237, t. 32, figs. 1 & 2 (1878) & Lich. Fl. ed. 3, p. 324.
Specimen not seen.
Considered by Leighton to be allied to the preceding, but differs in
the appearance of the apothecia and in the larger spores. By the
contiguous growth of several plants on the same stone, the surface
becomes intersected by dark lines.
Hab. On bluish-grey slates.—Distr. Eare in hilly regions in
Wales.
24. B. suhdisciformis J a t ta Syll. Lich. Ita l. p. 392 (1900).
—Thallus determinate, thickish, minutely cracked-areolate, the
areoiæ plane, sordid-yellowish-white (K + yellow then red,
CaCl —, medulla I — ) ; hypothallns black, limiting the thallus.
Apothecia sessile, plane, marginate, blackish, more or less pruinose,
the margin thick, entire, paler ; hypothecium black ; paraphyses
discrete; hymenium pale-brown; spores oblong, brown, 0,011-16
mm. long, 0,007-8 mm. thick.—Lecidea suhdisciformis Leight.
Lich. FI. p. 308 (1871) ; ed. 3, p. 322.
Exsicc. Larb. Lich. Cæsar. n. 35.
Distinguished from allied species by the strongly marked hypo - ,
thallus which occasionally intersects the thallus, and by the chemical
reaction.
Hah. On rooks.—Distr. Somewhat rare in the Channel Islands,
S. and Central England, Wales and N. and W. Ireland.—B. M. Jer-
bourg, Guernsey ; Noirmont, Jersey ; Sark ; Lamorna, Cornwall ;
Torquay, Devon; North Hill, Malvern, Worcestershire; Conway,
Carnarvonshire; Kinsale, Cork.
Var. meiosperma Steiner in Verb. K. K. Zool.-Bot. Ges.
Wien Ivii. p. 363 (1907).—Thallus as in the type. Apothecia
often bluish-grey pruinose ; spores smaller, 0,009-12 mm. long,
0,005-7 mm. thick.—Lecidea disciformis var. meiosperma Nyl. in
Flora li. p. 478 (1868); Cromb. Lich. Brit. p. 88. L. suhdisciformis
var. meiosperma Leight. Lich. FI. p. 308 (1871) ; ed. 3,
p. 322.
Hah. On rocks.—Distr. Eare in the Channel Islands.—B. M.
Jersey; the Bperquerie, Sark.
25. B. disciformis Mudd Man. p. 216 (1861) pro p a rte .—
Thallus determinate, thin, smooth, continuous, unequal or
cracked-areolate, whitish or greyish-white, (K + yellow, CaCl — ) ;
hypotballus thin, black, limiting the thallus. Apothecia sessile,
moderate or somewhat small, plane and thinly margined, a t
length convex and almost immarginate, black ; hypothecium
dark-brown or black ; paraphyses subconcrete, brownish a t the
apices, branched and capitate; spores ellipsoid or oblong,
0,019-30 mm. long, 0,008-0-014 mm. thick ; hymenial gelatine
bluish with iodine.—Lecidea disciformis Nyl. in Bot. Not. 1852,
p. 175 ; Cromb. Lich. Brit. p. 88 ; Leight. Lich. FI. p. 305 ;
ed. 3 p. 317. Lecidea parasema var. disciformis Fr. Nov. Sched.
Crit. p. 9 (1826).
Exsicc. Leight. n. 180; Mudd n. 187; Carroll Lich. Hib.
n. 19 ; Johns, n. 388.
Often confounded by authors with L. parasema, from which,
among other differences, the character of the spores renders it very
distinct. The thallus, at times little visible, is occasionally entirely
evanescent (form ecrustaoea Nyl. in Act. Soo. Linn. Bord. sér. 3, i.
p. 387 (1856)). The apothecia are numerous, but usually somewhat
scattered. The minute black spermogones, which are not unfrequent,
have slender straight spermatia 0,004-5 mm. long, 0,001 mm. thick.
Hab. On the smooth bark, very rarely on denudate trunks of trees
in upland districts.—Distr. General and not uncommon in Great
Britain, rarer in S. Ireland, not seen from the Channel Islands._
B. M. Sevenoaks, Kent ; St. Leonards Forest, Sussex ; near Lyndhurst,
New Forest, Hants; Ullacombe, Bovey Tracey, S. Devon;
Launceston, Cornwall ; Nannau and Garth, Dolgelly, Merioneth ;
Bettws-y-Coed, Carnarvonshire; Llanforda and Haughmond Hill,
Shropshire; Kildale and Newton Wood, Cleveland, Yorkshire; Eglestone,
Durham ; Windermere, Westmoreland ; Baroaldine, Argyll ;
Kenmore, Killin, Glen Lochay, Glen Falloch and Aberfeldy, Perthshire;
Barcaldine, Argyll; Banchory Devenick near Aberdeen, and
Castleton of Braemar, Aberdeenshire ; Lairg, Sutherlandshire ; Appleoross,
Rossshire ; Glenbower Wood and Old Deer Park, Castle Martyr,
Cork; Muckross and Croghan, Killarney, Glenoar and Blaokwater
Bridge, Old Dromore, Kerry.
Var. saxícola Oliv. Exp. Syst. Lich. ii. 2, p. 145 (1901).__
Thallus tartareous, smooth, unequal, cracked-areolate, the areolæ
contiguous, whitish or greyish; apothecia numerous, becoming
convex and immarginate, sometimes 2- or 3-aggregate, somewhat
scabrid ; hypothecium reddish- or blackish-brown ; paraphyses
discrete, brown a t the tips, branched and capitate; spores
ellipsoid, 0,018-22 mm. long, 0,09-11 mm. thick.
Agreeing with the species in the general characters but differing in
the somewhat thicker thallus, the smaller spores, and the saxicolous
habitat.
Hab. On rocks.—B. M. Near Land’s End, Cornwall.
Var. insignis A. L. Sm.—Thallus effuse, thin, warted-
granular, whitish. Apothecia rather large, usually plane; spores
large, 0,018-32 mm. long, 0,011-16 mm. thick, otherwise as in
the species.—Buellia insignis var. corticicola Koerb. Syst. Lioh.
Germ. p. 230 (1855) ; Leight. in Grevillea i. p. 134. (1873).
Lecidea insignis var. muscorum Næg. in Hepp Flecht. Eur. n. 40
(1853) ; f. corticicola Leight. Lioh. El. ed. 3, p. 314 ; L. disciformis
subsp. insignis Nyl. ex Norrl. in Not. Sallsk. Eaun. & El. Penn,
n. ser. x. p. 340 (1873).
Differs from the species in the habitat and in the generally larger
spores. Leighton {II. o.) records only the f. corticicola (Koerb. I. c.)
I I . N