302 PYRKNOCARPEl fpOLYBLASTIA 



t. 1711 (1807) (non Ach.). Lithocia Schraderi 8. F. Gray Nafc. 

 AiT. i. p. 497 (1821). 



The perithecia are thickly scattered over the stone and tend to 

 grow in concentric lines. There are also present on the surface of the 

 stone small gioups of Verrucaria Dufourii, probably the " male 

 scattered warts" of Smith's description. 



Hab. On chalk or calcareous stones. — B. M. Sussex (the only 

 locality) ; specimen collected by W. Borrer. 



5. P. deminuta Arn. in Flora xliv. p. 264 (1861).— Thallus 

 greyish- white, thin, tartareous. Perithecia globose, minute, black, 

 entirely immersed, leaving pits in the rock, the ostiole slightly 

 prominent ; perithecial wall entire ; paraphyses none ; spores 8, 

 colourless then brown, ellipsoid or broadly oblong, muriform, 

 0,022-30 mm. long, 0,012-15 mm. thick. — Verrucaria deminuta 

 Cromb. in Journ. Bot. xiv. p. 363 (1876) ; Leight. Lich. Fl. ed. 3, 

 p. 491. 



This and the preceding are the only British species of Polyblastia 

 that form perithecial pits (foveolate) in the substratum. 



Hab. On moist rocks. — B. M. Recess Road, Connemara, Galway. 



6. P. inumbrata A. L. Sm. — Thallus dark-brownish or greyish, 

 thin, effuse, unequal or dispersed. Perithecia moderate in size, 

 semi-immersed, the ostiole projecting, generally with a minute 

 papilla ; perithecial wall thick, black, entire ; paraphyses muci- 

 laginous, disappearing ; spores 8 in the ascus, oblong-ellipsoid, 

 light -yellowish -brown, muriform, large, 0,33-62 mm. long, 

 0,017-32 mm. thick; hymenial gelatine wine-red with iodine. — 

 Verrucaria inumhraia Nyl. in Flora xlvii. p. 355 (1864) ; Carroll 

 in Journ. Bot. iii. p. 292 (1865); Cromb. Lich. Brit. p. 114: 

 Leight. Lich. Fl. p. 460 ; ed. 3, p. 492. 



Nylander describes the spores as colourless, but in the authentic 

 specimens examined they are a clear light-brown with very distinct 

 1-3 transverse septa and muriform with small cells. 



Hab. On schistose rocks. — B. M. Ben Lawers (the only locality). 



7. P. subviridicans A. L. Sm. — Thallus pale-greenish, thin, 

 continuous and wrinkled. Perithecia black, embedded in large 

 thalline tubercles, the ostiole papillate, small, depressed ; peri- 

 thecial wall dimidiate ; paraphyses none ; spores 2 or 4 in the 

 ascus, oblong, colourless, muriform, large, 0,046-70 mm. long, 

 0,024—30 mm. thick. — Verrucaria subviridicans Nyl. in Flora ix. 

 p. 566 (1877); Cromb. in Grevillea vi. p. 114; Leight. Lich. Fl. 

 ed. 3, p. 488. Specimen not seen. 



Considered by Nylander to be very like the preceding, of which it 

 may be a subspecies. He also states that the thallus contains blue- 

 green algae (gonimiose) ; that may however be accidental, and due to 

 the moist habitat. 



Hab. On stones in torrents, rare in W. Ireland, near Kylemore, 

 Connemara, Galway. 



