Hdb. On peaty earth between the squamules of Dermatocarpon
cinereum. — B. M. Ben Lawers, Perthshire (the only British
locality).
16. P. gothica Th. Fr. in Bot. Not. 1865, p. 112.—Thallus
thin, greenish or dark-coloured, effuse. Perithecia black, small,
semi-immersed, the ostiole indistinct ; peritheciai wall entire ;
paraphyses indistinct ; ostiolar filaments short ; ascus rather
broad, subventricose ; spores ellipsoid, becoming somewhat fusiform,
dark-brown, a t first 3- then 5-7-septate and irregularly
muriform, 0,018-28 mm. long, 0,007-9 mm. thick.— Verrucaria
pituphloia Leight. Lich. Fl. p. 458 (1871) (fide Th. Fr. in K.
Svensk. Vetensk. Soc. Nov. Act. 1877, 8, p. 26). V. gothica
Leight. tom. cit. ed. 3, p. 490 (1879).
Th. Fries ((. o.) recognizes the resemblance of this species to a
Sphæria. I have been unable to detect gonidia in Leighton’s specimen,
but the size and structure of the spores agree with Fries’s description.
Hdb. On decaying mosses and humus (P. gothica) ; on larch-poles
[V. pituphloia).—Distr. Shrewsbury, Shropshire.
17. P. ? peltophora A. L. Sm. — Thallus squamulose, the
squamules thin, green, smooth, either aproxímate or scattered.
Perithecia black, large, prominent ; peritheciai wall dimidiate ;
paraphyses few, filiform, interspersed with oily granules ; ostiolar
filaments (periphyses) numerous ; spores 8 in the ascus, dark-
brown, ellipsoid, muriform, rather large, 0,035-48 mm. long,
0.020-30 mm. thick ; hymenial gelatine wine-red with iodine.—
Verrucaria peltophora Stirton in Grevillea iii. p. 37 (1874) ;
Leight. Lich. Fl. ed. 3, p. 486. Specimen not seen.
Hab. On the earth, Ben Lawers, Perthshire.
108. THROMBIUM Wallr. Fl. Crypt. Germ. 1, p. 287
(1831) ; emend. Massal. Ric. Lich. p. 156 (1852). Inoderma
S. F. Gray Nat. Arr. i. p. 498 (1821) pro parte. Verrucaria
subgen. Inoderma Ach. Lich. Univ. p. 294 (1810). (Pi. 44.)
Thallus crustaceous, uniform, membranaceous, mucilaginous,
thin, sometimes developed within the substratum or altogether
wanting. Algal cells Pleurococcus. Perithecia simple, immersed
in the thallus or superficial, the outer wall of a carbonaceous
or horny structure, light or dark-coloured, opening by a poriform
ostiole; paraphyses slender, branched, persistent; asci 4-8-spored;
spores ellipsoid, simple, colourless or Iqrownish.
The only British genus of simple-spored Verrucariaceæ with
persistent paraphyses. Aoharius’s subgenus Inoderma represented
species of Verrucaria with a somewhat soft thallus. S. F. Gray
raised it to generic rank and included in it two British species,
1. epigæa and I. byssacea, the latter of doubtful position.
1. Thr. lætevirens A. L. Sm.—Thallus forming a broadly
effused rather thick inseparable film, smooth, even, rather
gelatinous, bright olive-green, the lobed margin paler and
yellowish; gonidia protococcoid, globose, 0,012-15 mm. in
diameter. Perithecia minute, crowded, globose, entire, black,
completely immersed in the thallus with a minute black ring
round the ostiole ; asci clavate ; spores ellipsoid, simple, colourless,
0,011-12 mm. long, 0,006 mm. th ic k ; paraphyses scanty,
slender, cylindrical ; spermogones immersed, mixed with the
perithecia, with filiform straight sterigmata and simple cylindrical
straight spermatia, 0,008-9 mm. long, 0,002 mm. thick.
— Verrucaria lætevirens Massee in Journ. Bot. xxx. p. 193,
t. 324, figs. 1-9 (1892).
Differs from other maritime simple-spored forms in the presence of
paraphyses.
Hdb. On smooth rocks between tide-marks.—Distr. Somewhat
rare on Northern, East and West coasts (Berwick-on-Tweed, Northumberland
; Burnmouth, Berwickshire ; Gareloch, Dumbartonshire ;
Cumbrae, Buteshire; Loch Goil, Argyll).
2. Thr. epigæum Wallr. Naturgesch. Flecht. p. 265 (1825)
(nomen) & PI. Crypt. Germ. i. p. 294 (1831).—Thallus pale-
brown, or yellowish-green, thin, effuse, gelatinous when moist,
somewhat furfuraceous when dry. Perithecia small, black, globose,
immersed in the thallus, the upper p art only visible ; peritheciai
wall entire, thicker above ; spores oblong, ellipsoid or irregularly
ovate, ra th e r large, 0,018-25 mm. long, 0,005-011 mm. thick.
—Sphæria epigæa Pers. Syn. Fung. Add. p. xxvii. (1801).
Verrucaria epigæa Ach. Meth. p. 123 (1803); Hook, in Sm.
Engl. El. V . p. 155 ; Tayl. in Mackay Fl. Hib. ii. p. 96 ; Leight.
Angioc. Lich. p. 64, t. 27, fig. 4 & Lich. Fl. p. 415 ; ed. 3,
p. 446; Mudd Man. p. 293; Cromb. Lich. Brit. p. 116. Lichen
terrestris Sm. Engl. Bot. t. 1681 (1807). Inoderma epigæa
S. E. Gray Nat. Arr. i. p. 498 (1821).
Hab. On soil.—Distr. Eather rare throughout the British Isles.—
B. M. Hassocks, Maresfield and Tilgate, Sussex ; Cradley, Herefordshire
; Hales End near Malvern, Worcestershire ; Ross, Clare ;
Connemara, Galway.
3. Thr. thelostoma A. L. Sm.—Thallus reddish-brown, thin,
continuous, minutely cracked-areolate, suborbicular and determinate.
Perithecia reddish-brown, sessile, hemispherical, becoming
widely depressed round the ostiole ; peritheciai wall entire,
reddish-brown above, paler below ; paraphyses slender, threadlike,
sometimes branched ; spores ellipsoid, colourless, 0,017—20
mm. long, 0,009-010 mm. thick, or sometimes rather larger.—
Verrucaria thelostoma Ach. ex Harrim. in Winch Bot. Guide
ii. p. 44 (1807); Mudd Man. p. 293 ; Leight. Lioh. El. p. 421 ;
ed. 3, p. 452. Lichen thelostomus Sm. Engl. Bot. t. 2153 (1810).
Pyrenula umbonata Ach. Lich. Univ. p. 316 (1810); S. F. Gray
Nat. Arr. i. p. 493. Segestria thelostoma Fr. Lich. Eur. p. 429
X 2