thecia innate, immarginate, roundish or somewhat elongate and
irregular ; asci ovate-pyriform, thickened a t the apices ; spores
ovate-elliptical, septate then muriform, colourless or brownish;
paraphyses indistinct, branched, coherent.
5Vith the general characters of Arthonia, but differing in the
muriform spores.
1. A. dispersum Mudd Man. p. 252, t. 4, f. 99 (1861).—
J hallus greyish-white or cream-coloured, thin, membranaceous,,
smooth. Apothecia small, innate, plane, simple or minutely
radiate, congregate in small groups, brownish-black; spores
oblong, muriform, colourless, 0,021-27 mm. long, 0,010-15 mm.
th ic k ; hymenial gelatine blue, the asci wine-red, with iodine.—
Opegrapha dispersa DC. PI. Pranc. p. 308 (1805) pro parte (fide
Nyl. in Mem. Soc. Sci. Nat. Cherb. iv. p. 93 (1856)). Arthonia
dispersa^ Duf. in Journ. Phys. Ixxxvii. p. 203 (1818) ; Carroll in
Nat. Hist. Rev. vi. p. 532 (1859). A. anastomosans Cromb. Lich.
Rrit. p. 103 (1870) ; Leight. Lich. Fl. p. 402 ; ed. 3, p. 425.
A. radiata var. anastomosans Ach. Lich. IJniv. p. 146 (1810).
^ Hah. On the smooth bark of trees, chiefly young oaks and hazel.—
Distr. Eare in S. England and S. Ireland.—B. M. Near Ullacombe,
Bovey Tracey, Devon; near Bantry Bay, Cork; Tore Mt., Croghan,
Old Dromore and Eagle’s Nest, Killarney, Kerry.
2. A. spectabile Massal. Ric. Lich. p. 54 (1852).—Thallus
whitish, effuse, thin, unequal, subfarinaceoiis. Apothecia brownish
black, rather large, angularly roundish, often surrounded by
a spurious thalline margin, scattered or crowded and subconfluent,
internally dark-coloured; spores oblong, septate, muriform,
colourless, becoming brown, 0,030—36 mm. long, 0,015 mm.
thick ; hymenial gelatine usually blue then wine-red with iodine.—
Arthonia spectahilis Plot, ex Massal. I. c. ; Carroll in Jo u rn Bot.
vi. p. 100 (1868); Cromb. Lich. Brit. p. 103 ; Leight. Lich. PI.
p. 402 ; ed. 3, p. 425.
Hah. On trees.—Distr. Eare in S. England, Wales and S. Ireland.—
B. M. Dartmoor, Devon; Dolgelly, Merioneth, Croghan, Killarney,
Derry.
GRAPHIDACEjE.
Thallus crustaceous. Algal cells Trentepohlia, or rarely
Palmella. Apothecia usually linear (lirellse), rarely oblong or
oval, simple or branched, sessile or erumpent, ma rg in a te ; paraphyses
simple or branched; asci elongate-clavate, spores simple
or variously septate or muriform, colourless or coloured.
The. more distinctly elongate apothecia, which have a well-
developed proper margin, distinguish Grapliidacea from the two
preceding Natural Orders. I t is represented in Britain by the
following genera :—
Thallus with Palmella gonidia ; apothecia oblong or oval.
Spores simple, colourless.
Hymenium simple,
Apothecia carbonaceous 85. L ith o g ra p h a .
„ not carbonaceous ... 86. X y lo g ra p h a .
Hymenium compound .................... 87. P ty c h o g ra p h a .
Spores 1-septate, brown............................ 88. E n c e p h a lo g ra p h a .
Thallus with Trentepohlia gonidia; apothecia elongate or roundish.
Spores 1-septate, colourless or brown ... 89. Me lasp ile a.
Spoies 3-pluri-septate.
Apothecia superflcial ........................ 90. Op eg rap h a .
Apothecia immersed.
Spores colourless........................ 91. G ra p h is.
Spores brown ............................ 92. P hæ o g ra p h is.
Spores muriform......................................... 98. G ra p h in a .
85. LITHOGrRAPHA Nyl. in Act. Soc. Linn. Bord. sér. 3
i. p. 393 (1856). (PI. 22.)
Thallus crustaceous, sometimes evanescent. Algal cells
Palmella. Apothecia shortly elongate, lirelliform, carbonaceous,
the disc usually narrow, the margins prominent, inflexed ; hypothecium
usually dark-coloured ; paraphyses very rarely discrete ;
asci clavate, 8- or poly-spored ; spores simple, colourless.
1. L. te sse ra ta Nyl. tom. cit. p. 441 & Lich. Scand. p. 290.—
Thallus thickish, verrucose-areolate or areolate-rimose, greyish,
pale-greyish-brown or whitish (K + yellow then reddish,
CaCl—). Apothecia moderate in size, ra th e r prominent, shortly
lirelliform, obtuse, simple or a t times divided, black, the margin
somewhat shining ; disc narrow; paraphyses irregular or indistinct ;
hypothecium thick, blackish-brown ; spores 8 in the ascus, oblong
or ellipsoid, 0,008-15 mm. long, 0,005-8 mm. th ick ; hymenial
gelatine pale-bluish then tawny-wine-red with iodine.—Mudd
Man. p. 225, t. 4. fig. 87 ; Cromb. Lich. Brit. p. 95 ; Leight.
Lich. Fl. p. 360 ; ed. 3, p. 393. Opegrapha tesserata DC. PI.
Franc, ii. p. 313 (1805) ; Borr. Engl. Bot. Suppl. t. 2632, f. 2 ;
Hook, in Sm. Engl. Fl. v. p. 146 ; Leight. in Ann. Mag. Nat.
Hist. ser. 2, xiii. p. 88, t. 5, f. 1 (1854).
Exsicc. Leight. n. 396.
The thalline areolse are either contiguous or somewhat scattered,
the black hypotballus being more or less visible. The apothecia,
variable in form, are either solitary or crowded and congested.
Hab. On rooks from upland to alpine situations in mountainous
regions. Distr. With certainty only in N. Wales, N. England, on the
Grampians, and in the N.W. Highlands of Scotland.—B. M. Near
Lyn Aran and Cader Idris, Merioneth; Capel Curig, Cwm Clyd,
Nant Francon, Snowdon, Carnarvonshire; near Stavely, Kendal,
Westmoreland ; Holwick Scar, Teesdale, Durham ; Ben Lawers,
Perthshire ; summit of Morrone, Braemar, Aberdeenshire ; Hills of
Applecross, Eossshire.