0,016-24 mm. long, 0,004-6 mm. thick.—Cromh. Lich. Brit,
p. 99; Leight. Lich. Fl. p. 378; ed. 3, p. 401.
Exsicc. Cromb. n. 195.
Differs from the preceding in the almost constant absence of
thallus, the more lax character of the paraphyses and the thinner
walled asci at the tips.
Hah. On rocks.—Distr. Rather rare throughout the British Isles.
—B. M. I. of Wight ; near Cirencester, Gloucestershire ; Aberdovey,
Merioneth ; Ayton, Cleveland, Yorkshire ; Achosragan, Appin, Argyll ;
Craig Tulloch, Blair Athole, Perthshire ; Dinish Island, Killarney,
Kerry ; Lettermore, Connemara, Galway.
13. 0. xanthodes Nyl. in Flora Ixi. p. 245 (1878).—Thallus
yellow or yellowish-grey, thin ra th e r smooth, cracked into minute
areolæ. Apothecia minute, oblong, black with a narro sv disc ;
hypothecium black ; paraphyses conglutinate ; spores fusiform-
oiilong, 3- sometimes 4-septate, colourless, 0,015-18 mm. long,
0,005-6 mm. thick ; hymenial gelatine wine-red with iodine ;
spermatia straight, 0,004 mm. long, 0,001 mm. thick.—Cromh.
ill Grevillea vii. p. 97 ; Leight. Lich. Fl. ed. 3, p. 404.
Well characterized by the areolate thallus and the minute scattered
apothecia.
Hah. On rocks.—B. M. Kylemore, Connemara, Galway (the only
locality).
14. 0. mirifica Stirton in Scott. Nat. 1879, p. 17.—Thallus
whitish or greyish, thickish, minutely cracked, sometimes nearly
granulose, sometimes farinaceous (K —, K.CaCl. + red). Apothecia
black, moderate in size, sessile, round or oblong, scattered
or aggregate ; disc pruinose or naked, a t first somewhat concave
and then acutely margined, a t length plane, often somewhat
convex and immarginate ; hypothecium black or fuscous-black,
thick ; paraphyses irregular, indistinct, apices clavate, nigricant ;
spores 8, colourless, oblong or obtusely fusiform, 3-septate, 0,014-
21 mm. long, 0,0035-45 mm. th ick ; hymenial gelatine wine-red
with iodine.—Leight. Lich. PI. ed. 3, p. 545. Specimen not seen.
Perhaps more nearly allied to Lecanactis than to Opegrapha.
Hab. On rocks, I. of Cumbrae.
Spores 0-7-septate.
15. 0. paraxanthodes Nyl. in Flora Ixii. p. 357 (1879).—
Thallus pale-yellow or pale-greenish, thin, minutely cracked-
areolate. Apothecia minute, oblong or linear-oblong, disc slitlike;
spores fusiform-oblong, 5- (sometimes 4-) septate, 0,023-25
mm. long, 0,008-9 mm. thick ; hymenial gelatine tawny-wine-
reddish with iodine ; spermatia straight, 0,005-7 mm. long,
0,0006 mm. thick.—Cromb. in Grevillea viii. p. 113 (1880).
Exsicc. Larb. Lich. Hb. without number.
Similar to 0. xanthodes, but distinguished by the larger spores.
Hab. On shady calcareous rooks.— B. M. Achnanure, Galway
(the only locality).
16. 0. varia Pers. in Ust. Ann. Bot. vii. p. 30 (1794).—
Thallus effuse, whitish, pulverulent, thin. Apothecia prominent,
black, sessile, roundish-oblong, elliptical, or elongate, often
attenuate a t each end ; the margins prominent, rather thin and
inflexed or often disappearing ; the disc forming a narrow slit or
dilated and plane, sometimes almost convex ; hypothecium dark-
brown ; paraphyses slender, wavy and branched, involved above
in a brown mucilage ; spores irregularly ovate-fusiform, usually
5-septate, colourless or becoming brownish, rather large, 0,020-30
mm. long, 0,007-9 mm. thick.—Hook, in Sm. Engl. Fl. v. p. 145
(excl. syn. 0. lichenoides and 0. notha) ; Tayl. in Mackay Fl.
Hib. ii. p. 106 (excl. syn. Engl. Bot. t. 1890 & 0. notha) ;
Leight. in Ann. Mag. Nat. Hist. ser. 2, xiii, p. 94, t. 5, f. 9
(1854) (incl. vars. pulicaris Pr. Lich. Eur. p. 364 (1831),
diaphora Fr. I. c. p. 365, tigrina Schær. Enum. p. 157 (1850) &
tridens Schær. I. c. p. 158) & Lich. Fl. p. 381 ; ed. 3, p. 404 (inch
ft’, pulicaris, diaphora, tigrina and tridens) ; Mudd Man. p. 229
(incl. vars. pulicaris, signata (Fr. I. c.), tigrina f. tridens Mudd
efe diaphora) ; Cromb. Lich. Brit. p. 97 pro parte. 0. diaphora
Ach. Meth. p. 19 (1803) ; Engl. Bot. t. 2280 ; 0. signata var.
tigrina A ch. Lioh. Univ. p. 262 (1810). Lichen scriptusvar. puUcaris
Lightf. Fl. Scot. ii. p. 801 (1777). L. pulicaris Hoffm. Enum.
Lich. p. 14, t. 3, f. 2, f. (1784)? L. diaphorus Ach. Lich. Suec,
Prodr. p. 20 (1798). L. signatus Ach. I. c. p. 23. Alyxoria
diaphora S. F. Gray Nat. Arr. i. p. 504 (1821).
Exsicc. Mudd n. 205 ; Leight. n. 287 (as 0. varia, var.
tigrina).
A very variable species in the form and size of the apothecia,
giving rise to numerous varieties which appear to be only forms or
stages of growth th a t are frequently represented side by side on the
same specimen. When the apothecia are rather small with the ends
rounded or tapering and the margins persistent and incurved, it is
f. pulicaris ; the apothecia are more elongate and obtuse in f. tigrina,
while in f. diaphora the margins tend to disappear, the disc becoming
rather wide and flat or slightly convex. Usually the apothecia are
simple, straight or bent and numerous, lying in all directions, sometimes
they are stellately arranged (f. tridens).
Lichen pulicaris Hoffm., though professedly based on Lightfoot’s
variety, is doubtful and incomplete both in description and
figure. Some recent lichenologists have rejected the name varia,
substituting as species 0. pulicaris, 0. diaphora and 0. notha. The
microsoopic characters of the apothecia are alike in all ; in 0. diaphora
the spermatia are slightly shorter and thicker, 0,003-4 nim.
long, 0,002 mm. thick ; in 0. pulicaris they are 0,004 mm. long and
0,001 mm. thick (fide Nyl. Lioh. Par. pp. 104-5 (1896)).
Hab. On trees.—Distr. Common in England and the Channel
Islands, rarer in Scotland and Ireland.—B. M. Jersey ; Appuldur-
combe, I. of Wight; Lustleigh, Devon; New Forest, H an ts; near
Shermanbury, Gravely, Wiston, Wakehurst Park, and St. Leonards,
Sussex; Canterbury, Kent; Eeigate, Surrey; near Millhill, Middlesex;
Quendon and Ulting, Essex; Hollybush Hill, Malvern, Little