MICKOTHELIA] PYRENULAOEjE 331 



1. M. miculaFlot. ex Koerb. Lich. Syst. Germ. p. 373 (1855). 

 — Thallus pale-whitish-brown, thin, smooth, effuse. Peritheoia 

 minute, black, hemispherical, semi-immersed ; perithecial wall 

 dimidiate ; spores 8 in the ascus, dark-brown, oblong, 1 -septate, 

 slightly constricted, the upper cell rather larger, 0,015-25 mm. 

 long, 0,005-7 mm. thick (usually about 0,017 mm. long, 

 0,005 mm. thick). — Yerrucaria Lyellii Leight. Angioc. Lich. 

 p. 42, t. 18, tig. 3 (1851)? V. cinerella Flot. ex Nyl. in Maine et 

 Loire Mem. Soc. Acad. iv. p. 60 (1858) & Lich. Scand. p. 281 

 (non JSTyl. in Ann. Soi. Nat. s6r. 3, iii. p. 174 (1855) ) ; Carroll 

 in Journ. Bot. iii. p. 293 (1865) ; Cromb. Lich. Brit. p. 121 ; 

 Leight. Lich. Fl. p. 437 ; ed. 3, p. 465. 



The species Verrucaria cinerella Nyl. (Ann. Sci. Nat. I. e.) is a 

 Chilian plant, and has faintly coloured large spores, measuring 

 0,032-36 mm. long, 0,009-011 mm. thick ; the characters of the 

 British specimens agree with those republished by Nylander in Lich. 

 Scand. I. c. 



Sab. On trees. — Distr. Rare in S. and W. England, more frequent 

 in S. and W. Ireland, not recorded from Scotland. — B. M. Sapperton, 

 Gloucestershire; Glengariff, Cork; Tore Mt., Crogham, Mangerton 

 and Dinish, Killarney, Lough Inohiquin, Glencar and Old Dromore, 

 Kerry. 



Yar. megaspora A. L. Sm. — Similar to the species but with 

 larger spores, 0,023-36 mm. long, 0,009-013 mm. thick — Yerru- 

 caria cinerella var. megaspora Nyl. in Flora li. p. 348 (1868) ; 

 Oromb. Lich. Brit. p. 121 & in Journ. Linn. Soc. xi. p. 490 

 (1871); Leight. II. c. Specimen not seen. 



Sab. On trees. — Distr. Rare in S. England, New Forest, Hants. 



2. M. atomaria Koerb. Syst. Lich. Germ. p. 373 (1855). — 

 Thallus thin, greyish. Perithecia minute, hemispherical, semi- 

 immersed, somewhat shining ; spores ellipsoid-oblong, 1-septate, 

 dark-brown, small, 0,012-14 mm. long, 0,004-6 mm. thick. — 

 Lichen atomarius Ach. Lich. Suec. Prodr. p. 16 (1798)? 

 Yerrucaria atomaria DC. Fl. Franc, ii. p. 313 (1805) ; Leight. 

 Lich. Fl. ed. 3, p. 467. 



Sab. On bark of hazel, &c. — Distr. Rare in W. Ireland, Kylemore, 

 Connemara, Galway. 



3. M. dispora A. L. Sm. — Thallus greyish-white, pulverulent, 

 very thin or disappearing. Perithecia minute, 0,150-200 mm. in 

 diameter, almost globose, shining, black, semi-immersed or almost 

 superficial, or leaving shallow pits in the substratum ; perithecial 

 wall black, rather soft, almost entire; paraphyses slender 

 branched and entangled ; asci elongate-clavate, somewhat 

 thickened at the apex, 0,065 mm. long, 0,015 mm. 'thick, 

 2-spored ; spores oblong, blunt or tapering at one or both ends, 



