Doubtful or parasitic.
9. Th. sparsulum A. L. Sm.—Thallus mclistinct. Perithecia
scattered, minute, subglobose ; peritheciai wall entire ; asci somewhat
saccate ; paraphyses mucilaginous, disappearing ; spores
colourless, ellipsoid, becoming 3-septate, 0,023-27 mm. long,
0,010-13 mm. thick.— Verrucarina sparsula Nyl. in Plora Ix.
p. 231 (1877); Cromb. in Grevillea vi. p. 20. Verrucaria sparsula
Leight. Lich. PI. ed. 3, p. 478.
The extremely minute perithecia are scattered over the substratum
either on the stone or on a thinly furfuraceous dark-brownish layer,
a mixture of various algæ and brown fungal hyphæ. Nylander (I. c.)
considered the blue-green algæ to be gonidiuiia and described the
lichen under a new genus Verrucarina akin to Pyrenidiaceæ. The
specimens in the British Museum are somewhat imperfectly developed ;
the connection is not clear between the perithecia and the gonidimia,
and the spores are immature and simple or only 1-septate.
Hab. On chalk.—Distr. Eare in S. England.—B. M. Lewes,
Sussex ; Dorking and Eeigate, Surrey.
10. Th. superpositum A. L. Sm.—Thallus none. Perithecia
minute, almost superficial, black, depressed globose, with a poriform
ostiole ; peritheciai wall entire ; paraphyses mucilagmous,
disappearing ; ostiolar filaments (periphyses) distinct ; asci obo-
vate-ellipsoid ; spores 8 in the ascus, colourless, ellipsoid-clavate,
1-septate, 0,017-19 mm. long, 0,006-8 mm. th ick ; hymenial
gelatine wine-red with iodine.— Verrucaria superposita Nyl. in
Flora xlviii. p. 357 (1865) ; Carroll in Journ. Bot. iv. p. 25
(1866); Cromb. Lich. Brit. p. 115; Leight. Lich. Fl. p. 462;
ed. 3, p. 494.
Hab. Parasitic on Polyblastia theleodes.—B. M. Ben Lawers,
Perthshire (the only locality).
107. POLYBLASTIA Massal. Ric. Lich. p. 147 (1852) ; emend.
Lonnr. in Plora xli. p. 630 (1858).—Sphseromphale Reichenb.
Consp. Reg. Veg. p. 20 (1828) pro p a rte ; Mudd Man. p. 281
pro parte. (PI. 43.)
Thallus variously crustaceous, not corticated, sometimes
developed within the substratum. Algal cells Pleurococcus.
Perithecia simple, superficial or immersed in the thallus, sometimes
embedded in the substratum and leaving pits ; ostiole a
simple pore ; paraphyses mucilaginous, disappearing ; asci broadly
clavate, 1-8-spored ; spores ra th e r large, ellipsoid, muriform,
colourless or dark-coloured.
Spores colourless.
1. P. intercedens Lonnr. in Flora xli. p. 631 (1858).—Thallus
greyish or dark-brownish, tartareous, thin, continuous or faintly
cracked, effuse or determined by a black line, sometimes obsolete.
p o l y b l a s t ia ] VEE ED CA E IA O BÆ 301
Perithecia moderate in size, black, prominent, immersed a t the
base, subhemispherical, usually somewhat depressed round the
poriform ostiole; peritheciai wall dimidiate; paraphyses none;
spores 8 in the ascus, colourless, rarely pale-brownish, ellipsoid,
muriform, the cells numerous, irregular, 0,024-42 mm. long,
0,015-21 mm. thick ; hymenial gelatine wine-red with iodine.—
Verrucaria intercedens Nyl. in Maine et Loire Mem. Soc. Acad,
iv. p. 33 (1858); Carroll in Journ. Bot. iii. p. 292 (1865);
Cromb. Lich. Brit. p. 1 1 4 ; Leight. Lich. Fl. p. 454 ; ed. 3,
p. 487.
Very variable in appearance aooording to the form of development.
In some specimens the perithecia are strongly umbilicate and are
comparable with those of Verrucaria Dufourii or Thelidium papulare;
in others the ostiole is scarcely visible.
Hab. On schistose, arenaceous and calcareous rocks.—DisZr. Rare
in mountainous regions in Scotland and N. England, but also recorded
from S. England.—E. M. Buxton, Derbyshire; Ben Lawers, Perthshire.
2. P. spurcella A. L. Sm.—Very similar to the preceding,
except for the thinner, obscurely smoky thallus ; spores colourless,
murali-locular, 0,022-25 mm. long, 0,011-14 mm. thick.— Ferrw-
caria spurcella Nyl. ex Shackleton & Hebden in Naturalist,
1892, p. 17. Specimen not seen.
Hab. Limestone walls (Malham, Gordale, Yorkshire).
3. P. fuscoargillacea Anzi in Comm. Soc. C ritt Ita l. ii. 1,
p. 26 (1864).—Thallus brownish- or w h itish -g re y th in , effuse,
minutely cracked-areolate, becoming farinose. Perithecia black,
small, numerous, often crowded, sessile, hemispherical, the base
only immersed, the ostiole poriform; peritheciai wall dimidiate ;
paraphyses disappearing ; spores 6 to 8 in the ascus, ellipsoid,
colourless or faintly yellowish, muriform, 0,018-28 mm. long,
0,011-16 mm. th ic k ; hymenial gelatine reddish with iodine.—
Verrucaria fuscoargiUacea Cromb. in Journ. Bot. ix. p. 179
(1871); Leight. Lich. Fl. p. 455 ; ed. 3, p. 487.
Hah. On rooks, mostly calcareous.—Distr. Eare in W. England,
N. Scotiand and W. Ireland.—E. M. Craig Tulloch, Blair Athole,
Perthshire.
Spores colourless becoming
4. P. Schraderi A. L. Sm.—Thallus greyish-white, thin,
tartareous and somewhat farinose. Perithecia black, globose,
deeply immersed and leaving pits in the rock, the ostiole only
slightly emerging; peritheciai wall e n tire ; spores 8 in the ascus
ellipsoid, muriform, usually 3-septate with an irregular longitudinal
division, colourless, becoming brownish, about 0,040-45 mm.
long, 0,012-17 mm. thick.—Lic/icn Schraderi Sm. Engl. Bot.