opegraphaJ graphidace^ 229 



Separated from Lithographa by the septate spores, but the species 

 requires reinvestigation. 



Hab. On slaty maritime rocks. — Distr. Very rare, found only in 

 Wales (Barmouth, Merioneth). 



9. M. vermifera Leight. in Trans. Linn. See. ser. 2, i. p. 146, 

 t. 22. figs. 21-24 (1876).— Thallus obsolete. Apothecia black, 

 minute, irregularly angular, oblong, imbedded in the cortical 

 layer, when dry plane and surrounded by a minute upraised 

 jagged margin of the cortical layer, when wet somewhat convex 

 and immarginate ; hymenium pale ; paraphyses slender, pale at 

 the apices ; asci linear-obovate ; spores innumerable, arranged 

 spirally in the ascus, colourless, cylindrical-fusiform, pointed, 

 vermiform, 1-septate. — Leight. Lich. Fl. ed. 3, p. 437. Specimen 

 not seen. 



Hah. Parasitic on thallus and apothecia of Pertusm-ia glohulifera ; 

 Trefriw, Carnarvonshire. 



10. M. Patersoni Stirton in Scott. Nat. iv. p. 29 (1877).— 

 Thallus whitish or pale, thin or evanescent. Apothecia small, 

 black, plane or somewhat convex ; hypothecium brownish or 

 pale ; paraphyses slender, somewhat branched, apices interwoven, 

 dark ; spores 4 or 5 in the ascus, colourless, acicular-cylindrical, 

 pluriseptate or 10-septate, breaking up at the septa, 0,040- 

 60 mm. long, 0,0025-30 mm. thick. — Specimen not seen. 



An aberrant species requiring further investigation. 



Hah. On dead bark ; Ben Brecht, Argyll. 



90. OPEGRAPHA Humb. Fl. Friberg. p. 57 (1793). (PI. 27.) 

 — Thallus crustaceous, superficial or developed under the bark 

 (hypophloeodal), thin or sometimes almost wanting. Algal 

 cells TrentepoMia. Apothecia (lirellse) black and carbonaceous, 

 superficial, elongate or roundish, simple or branched, with a 

 proper margin only ; disc narrow and slit-like or somewhat 

 flattened and plane ; asci clavate or elongate, usually 8-spored ; 

 spores colourless, sometimes becoming brownish, linear-oblong, 

 fusiform or acicular, pluriseptate. 



Spores 2>-septate, 



1. 0. herpetica Ach. Meth. p. 23 (1803).— Thallus thin, more 

 or less cracked or rugged, grey or usually olivaceous, effuse or 

 limited by a brown line. Apothecia small, innate, oval, oblong 

 or linear, obtuse, simple or forked, straight or curved ; margins 

 thick, rounded and inflexed, the disc slit-like, dilated in age ; 

 spores fusiform, 3-septate, colourless or pale-yellow, 0,017—27 mm. 

 long, 0,004-5 mm. thick ; spermogones with arcuate spermatia 



