94 LICHENES. [Verrucaria. 



our specimens the nucleus itself is pale, semitransparent, and gelati- 

 nous when moist, yet it is not readily discoverable, being enveloped in 

 a black crust. A variety on walls and on limestone at Dunkerron has 

 the thallus compact, and the apothecia oftener conical ; which, I sup- 

 pose, is the 0. nigrescens of Acharius, and V. nigrescens of Eng. 

 Flor* v. 5, /?, 155. 



27. V. acrotella, ACH. Thallus thin, dispersed, piano-gra- 

 nulate, of an olive-brown, sometimes nearly wanting ; apothecia 

 minute, at length thickly set, convex, papillose or porous on 

 the summit, roughish, black. Ack. Meth. Lich. p. 123. Eng. 

 Bot. t. 17J2, (the young state.) 



On flints, near Belfast, Mr. Templeton. On Carig mountain, 

 County of Kerry. Acharius, in his Lich. Univ. p. 293, appears to 

 have been imperfectly acquainted with this species, and hence has 

 made it a variety of the V. striatula of Wahlenberg, from whose 

 description of the thallus that of ours widely recedes : the nucleus is 

 whitish, semitransparent, and gelatinous when moist, and has no peri- 

 thecium passing under it. Mr. Templetori's specimens on flint have 

 the apothecia nearly twice as large as in the common appearance in our 

 mountains ; the apothecia, too, while destitute often of any thallus 

 adhering, yet have much black matter, similar to that of their perithe- 

 cium, around their bases. 



28. V. polysticta, BORR. Thallus of. minute tartareous, very 

 thin, crowded, angular, even, whitish scales, upon a thick 

 rimose, black substratum ; apothecia minute, immersed, at length 

 slightly emerging, plano-convex above, the pore obsolete. 

 Borr. in Eng. Bot. Supp. t. 2741. 



On the old walls of Dunkerron Castle. Our plant has the apo- 

 thecia more frequently dimpled ; in all other respects it entirely cor- 

 responds with Mr. Borrer's specimens. 



29. V. rubiginosa. Thallus indeterminate, subtarareous, 

 very thin, smooth, slightly cracked, of a pale olive-grey, on a 

 black substratum ; apothecia very minute, hemispherical, the 

 thallus rising about their base, their tops depressed, with a wide 

 pore, of a rust colour. 



On siliceous rocks at Blackwater, County of Kerry. The black 

 substratum is perceptible through the cracks of the thallus ; the cracks 

 are not continuous. The apothecia, not visible distinctly to the naked 

 eye, in many instances seem sessile on proper circular portions of the 

 thallus ; their pore is wide ; the nucleus pale, semitransparent, and 

 gelatinous when moist, beneath which the rust coloured perithecium 

 does not pass. This species has some affinity to Lecidea rupestris 

 in a young state, but the generic character is very different and very 

 distinct ; the thallus, too, is more even and smooth : besides, the 

 Lecidea is confined to calcareous rocks or mortar. 



30. V. irrigua. Thallus indeterminate, when moist of a 

 greenish-grey or olive-brown, and subgelatinous, when dry very 

 slightly cracked, filmy towards the edges ; apothecia of a middle 

 size, thickly set, hemispherical, minutely papillose, pale-reddish, 

 pellucid when moist. 



