0,006-8 mm. long, 0,002 mm. thick (fide Nyl. Lich. Par. p. 107
(1896)).—Engl. Bot. t. 1789 ?; Leight. in Ann. Mag. Nat. Hist,
ser. 2, xiii. p. 205, t. 5, f. 12a (1854) & Lich. Fl. p. 373 ; ed. 3,
p. 396 (incl. vars. vera and rubella) ; Mudd Man. p. 234 (incl.
vars. vera and riifescens with var. i-ubida pro parte) ; Carroll in
Journ. Bot. iii. p. 291 (1865) ; Cromb. Lich. Brit. p. 99 (incl.
var. disparata Ach. Syn. p. 73 (1814)). 0. rufescens Pers. in
Ust. Ann. Bot. vii. p. 29, t. 2, f. 3a (1794) ? ; Hook, in Sm. Engl.
IT. V. p. 144?; Tayl. in Mackay Fl. Hib. ii. p. 105? 0. ruhida
Chev. Hist. Graph, p. 80, t. 18, ff. 1 & 2 (1824). Lichen herpeticus
Ach. Lich. Suec. Prodr. p. 20 (1798). Hysterina herpetica S. F.
Gray Nat. Arr. i. p. 506 (1821). H. disparata S. P. Gray I. c.
Lxsicc. Leight. n. 221 ; Mudd n. 214.
Hab. On trees.—Distr. Eather frequent throughout the British
Islands.—-B. M. Near Ilsham, Torquay, and near Exeter, Devon;
near Lyndhurst, Hants; Hockley Woods, Essex; Charlton Forest,
Berks; Oxford; Derbyshire; Airyholme Wood, Basby Wood, Ayton
and Ingleby, Cleveland, Yorkshire ; near Cartland Crags, Lanarkshire ;
Dunkeld, Perthshire.
Var. elegans Borr. ex Leight. in Ann. Mag. Nat. Hist. ser. 2,
xiii. p. 207 (1854).—Thallus slightly pulverulent or scurfy.
Apothecia small, curved and wavy, often stellate.—Mudd Man.
p. 235 ; f. elegans Leight. Lich. Fl. p. 374 ; ed. 3, p. 397. Var.
rubida Mudd I. c. pro parte.
Lxsicc. Leight. n. 286.
Hab. On trees.—Distr. Somewhat rare in England and Ireland.—
B. M. Ivybridge and Ilsham, Torquay, Devon ; near Minstead, New
Forest, Hants ; St. Leonard’s Forest, Sussex ; near Bath, Somerset ;
Hollybush Hill, Malvern, Worcestershire ; Airyholme Wood and
Ingleby, Cleveland, Yorkshire.
Var. fuscata Schær. Enum. p. 156 (1850).—Thallus dark,
dingy-olive, otherwise as in the species.—0. herpetica var.
rufescens Mudd Man. p. 235 (1861) ^x c l. syn.), (& var. rubida
Mudd I. c. pro parte) ; Cromb. Lich. Brit. p. 99 ; form rufescens
Leight. Lich. Fl. p. 375; ed. 3, p. 397 pro parte. 0 . rubella
Pers. I. c. p. 31?; Sm. Engl. Fl. t. 2347 (1811); Hook, in Sm.
Engl. Fl. V. p. 144. Lichen rubellus Ach. Lich. Suec. Prodr.
p . 22 (1798).
Distinguished by the dark thallus. The species 0. rufescens has
been restricted by Nylander (Lich. Par. p. 107 (1896) ) to forms similar
to 0. herpetica, but with straight spermatia, 0,004-5 mm. long,
0,001 mm. thick, a character I have been unable to verify in any of
our British specimens.
Hab. Cn trees.—Distr. Not uncommon in England and Wales.—
B .M . Cirencester, Gloucestershire; Chalkney Woods, White Colne,
Hadleigh Woods, Ulting, Hatfield Peverel and Epping Forest, Essex;
Patcham, near Worcester; Gopsall Wood, Leicestershire; Suffolk;
Ingleby, Yorkshire.
Form arthonoidea Leight. Lich. Fl. ed. 3, p. 397 (1879).—
Thallus as in the preceding variety. Apothecia suborbicular,
innate, immarginate, plane.— Opegrapha rufescens var. arthonoidea
Schær. Spicil. p. 328 (183.6).
Hab. On ash trees.—Distr. Bare in England.—B. M. Chalford,
Gloucestershire.
Var. suhocellata Ach. Syn. p. 73 (1814).—Thallus somewhat
pulverulent. Apothecia small, oblong, simple or substellate,
embedded in the thallus and surrounded by a white margin.—
Leight. in Ann. Mag. Nat. Hist. ser. 2, xiii. p. 206 (1854) &
Lich. Fl. p. 374; ed. 3, p. 3 96 ; Mudd Man. p. 234; Cromb.
Lich. Brit. p. 99.
Lxsicc. Leight. n. 222.
Begarded by Nylander as a variety of 0. rufescens. It is easily
recognized by the spurious white margin of the apothecia. The
spermatia in our British specimens so far as observed are minute and
somewhat ovoid, 0,003 mm. long and 0,001-2 mm. thick.
Hdb. On trees.—Distr. Frequent in N. and S. England, rare in
Wales, the Channel Islands, and Ireland.—B. M. Near Exeter and
near Becky Falls, Devon ; New Forest, Hants ; near Bath, Somerset ;
Tilgate, near Clayton ; near Glynde and Baloombe, Sussex ; Epping
Forest, Essex ; Airyholme Wood, Easby Wood, and Cliffrigg, Cleveland,
Yorkshire ; Killarney, Kerry.
2. 0. contexta Stirton in Grevillea iii. p. 35 (1874).—Thallus
reddish-buff-coloured, thin, limited by the brown hypothallns.
Apothecia small, black, flattened, roundish, usually aggregate,
the disc gyrose-plicate ; hypothecium blackish-brown ; paraphyses
indistinct ; spores fusiform, blunt a t the apices, 3-septate,
colourless, 0,017-25 mm. long, 0,0045 mm. thick.—Leight. Lich.
Fl. ed. 3, p. 403. Specimen not seen.
Perhaps only a form of the preceding.
Hab. On elm, near Grantown, Invernessshire.
3. 0. atra Pers. in Ust. Ann. Bot. vii. p. 30 (1794).—
Thallus thin, forming whitish or yellowish patches, sometimes
limited. Apothecia black, numerous, lying in all directions or
subparallel, linear, usually simple, flexuose ; disc slit-like, narrow,
uniform, the margins thick, elevated, wavy ; hypothecium dark,
reddish upward ; spores obovate-fusiform, 3- or rarely 4-septate,
colourless, ra th e r small, 0,014-20 mm. long, 0,004 mm. thick.—
Hook, in Sm. Engl. Fl. v. p. 145 pro parte ; Tayl. in Mackay Fl.
Hib. ii. p. 105 ; Leight. in Ann. Mag. Nat. Hist. ser. 2, xiii.
p. 203, t. 5, f. 11 (1854) & Lich. Fl. p. 375 ; ed. 3, p. 3.98
(incl. f. tenuior Nyl. ex Leight. I. c. ed. 3, p. 400 (1879)); Mudd
Man. p. 232 ; Cromb. Lich. Brit. p. 98 pro parte. 0. denigrata
Sm. Engl. Bot. t. 1753 (1807) (non Ach.).
Lxsicc. Mudd nos. 208, 206 ; Leight. n. 220 (the two la tte r