BRITISH LICHENS

260 GRAPIDDINEjE OPEGRAPRA
Exsicc. Leight. nos. 67, 242; M_udd n. 203; Larb. Lich. Rb.
n.275.
Differs from O. confluens in the ·white and usually more developed
thallus, the more crowded lirellre, the conglutinate paraphyses and the
thick apex of the ascus.
Hab. On rocks mostly calcareous or arenaceous, rarely on clay
Boil.-Distr. General throughout the Channel Islands and England,
rarer in Scotland and Ireland.-B. M. St. Ouen's Bay, Jcrsey; Bodmin,
Cornwall; Kingsbridge and Torquay, Dovon; Ventnor, I. of Wight;
Ardmgly, HastiI2gs and Keymer Church, Sussex; ncar Cirencester,
Gloucestershire; Bathampton, Somerset; Hereford; Lcigh Court,
Worcestershire; Yarmouth, Norfolk; Giltar Point, Tenby. Pembrokeshire;
Aberdovey, MerlOneth; Holyhead, Anglesea; Great Orme's
Head, Carnarvon; CastcIl-Dinas·Bran, Denblghshirc; Parson Drove,
Cambridgeshire; ColIingham, Ayton and Roseberry, Cleveland,
Yorkshire; Arnbarrow, Westmorland; North Berwick; Bay of Nigg,
Kincardineshuc; Thul'so, Sutherland; Kilbarl'ick Church, ncar
Dublin; Ross and Kilkee, Clare; Glenarm, Antrim; Louisburgh and
Achill Isl., Mayo.
Form heteromorpha A. L. Sm.-Thallus almost obsolete.
Apothecia more scattered than in the species and the groups
smaller, rather large and prominent, simple or sometimes branched;
internal structure similar.-Opegrapha utra val'. Chevallieri f.
heteromorpha Stiz. tom. cit. 21, t. 1, f. 5, a-to O. atra f. helemmorpha
Cromb. Lich. Brit. 98 (1870). O. saxicola val'. Ohevallieri
f. heterornorpha Leight. Lich. Fl. ed. 3, 402.
Exsicc. Larb. Lich. Rb. n. 77.
Hab. On maritime rocks.-Distr. Rare in the Channel Islands,
S. England, E. and W. Scotland and S. and W. Ireland.-B. M. Port
Moulin, Sark; Noirmont, Jersey; Wembury. Devon, Aberdovoy,
Merionoth; 1. of Man; Arnside, Westmorland; Bay of Nigg, Kincardineshire;
near Peterhead, Aberdeenshire; Barcaldme, Argyll;
Old Head of Kinsale, and RosteIlan, Cork; Twelve Pins and KIIlary,
Connemara, Galway.
12. O. contluens Stiz. in Flora xlviii. 75 (1865).-Thallus
greyish-green, effuse, thin or wanting. Apothecia usually
grouped in little masses, rarely solitary and scattered; sessile
simple, rather thick, cylindrical, straight or curved and contorted;
disc slit-like, becoming somewhat open, the margins rounded,
inflexed, becoming acute; paraphyses discrete, slightly swollen
and brown at the tips; spores colourless, elongate-ovate, 3-septate,
16-24 (J.long, 4-6 (J. thick.-Cromb. Lich. Brit. 99; Leight. Lich.
Fl. 378; ed. 3, 40l.
Exsicc. Cromb. n. 195.
Differs f'rom the preceding in the almost constant absence of
thallus, the grouping of the lirellro, the more lax character of the paraphyses
and the thinner walled asci at the tips.
Hab. On roeks.-Distr. Rather rare throughout the British Isles.
-D. M. I. of Wight, near Cirencestcr, Gloucestcrshire; Aberdovey,