THELIDIUm] VEERDCARIACBiE 299 



usually depressed round the ostiole ; perithecial wall dimidiate ; 

 paraphyses disappearing ; spores ellipsoid, 3-septate, very large, 

 colourless, 0,035-50 mm. long, 0,015-20 mm. thick. — Th. pyreno- 

 phorum Koerb. Syst. Lich. Germ. p. 353 (1856) pro parte; 

 Mudd Man. p. 294. Verrucaria papularis Fr. Lich. Eur. p. 434 

 (1831) fide Arn. V. Sprucei Oh. Bab. ex Leight. Angioc. Lich. 

 p. 54, t. 23, figs. 4-6 (1851). V. pyrenophora Leight. torn. cit. 

 p. 76 (non Ach.) & Lich. Fl. p. 442; ed. 3, p. 474; Cromb. 

 Lich. Brit. p. 112 pro parte. 



Exsicc. Leight. n. 319 ; Larb. Lich. Hb. n. 240. 



Often confused with Th. pyrenophorum, which it resembles in the 

 outward appearance of thallus and peritheoia, but distinguished by the 

 larger 3-septate spores. Leighton's note in Angioc. Lich. p. 76, 

 in which he states that he had examined an authentic specimen of 

 V. pyrenophora Ach., is at variance with Nylander's description of 

 that species (Maine et Loh-e Mem. Soc. Acad. iv. p. 26 (1858) ), and 

 with the Acharian specimens at the Linuean Society. 



Hab. On rooks in damp upland regions. — Distr. Bare throughout 

 England, Scotland and Ireland, not recorded from the Channel Islands. 

 — B. M. Whitecliffe Eocks near Ludlow, Craigf orda and Llanymynech, 

 Shropshire ; Egremont and Lamplugh, Cumberland ; Craig Calliach, 

 Perthshire ; Rosscarberry Bocks, Cork ; Ballaghbeana Gap, Kerry ; 

 Doughruagh Mts. and Kylemore, Connemara, Kerry ; Armagh. 



7. Th. microcarpum A. L. Sm. — Thallus whitish, slightly 

 greenish or greyish, farinose or evanescent. Perithecia minute, 

 black, solitary or congregate, hemispherical, sessile, opening by a 

 pore ; perithecial wall dimidiate ; paraphyses none ; spores colour- 

 less, oblong-ellipsoid, 3-septate, 0,026-32 mm. long, 0,012-14 ram. 

 thick ; hymenial gelatine wine-red with iodine. — Verrucaria micro- 

 carpa Davies ex Leight. Lich. PI. p. 442 (1871); ed. 3, p. 474. 



Hah. On chalk. — Distr. Bare in S. England. — B. M. Beeding 

 Downs, Plumptoii Downs and GljTide, Sussex. 



8. Th. incavatum Mudd Man. p. 295, t. 5, fig. 122 (1861).— 

 Thallus greyish-white, tartareous, thin, smooth or somewhat fari- 

 nose, continuous. Perithecia black, hemispherical-globose, with 

 a large ostiole, deeply immersed, leaving pits in the rock ; 

 perithecial wall entire ; paraphyses disappearing ; spores ellipsoid- 

 oblong, colourless, 3-septate, sometimes constricted at the septa, 

 0,035-53 mm. long, 0,012-21 mm. thick. — Verrucaria pyrenophora 

 var. incavata Nyl. ex Mudd I. c. ; Cromb. Lich. Brit. p. 112. 

 Verrucaria incavata Leight. Lich. PI. p. 445 ; ed. 3, p. 476. 



Uxsicc. Mudd n. 282. 



Distinguished from Th. papulare by the pit-forming perithecia. 

 The spores in the specimens examined are smaller than the measure- 

 ments given byLeighton II. c, varying in size from 0,035-40 mm. long 

 and 0,012-15 nun. thick. 



Hah. On calcareous rocks. — Distr. Rare in N. England, Wales and 

 W. Ireland. — B. M. Buxton, Derbyshire; Bilsdale, Yorkshire. 



