Vtrrucaria.] LICHENES. 93 



very faint swelling of the thallus about their base ; hemispherical, with 

 a decided pore, and sometimes two or three pores on their summit, 

 rather rough, prominent, large as poppy seeds, sometimes larger. The 

 nucleus moistened is gelatinous, semitransparent, of a pale flesh-colour. 

 It is contained in a proper black tegument that completely envelopes 

 it; but quite distinct from the broader, thicker, hemispherical perithe- 

 cium, which is deficient below the nucleus. This structure shows our 

 species to be very different from V. epipolcea, Ach. with which alone 

 it can be confounded, and associated with which it is found often on the 

 same wall or rock : besides it has never a reddish suffusion of the crust 

 so common in the other ; but when we consider that the thallus is de- 

 terminate, scarcely cracked, and the remarkable pores of the apothecia, 

 there remains but little doubt. From V. rupestris Schrad. the promi- 

 nence of the apothecia, their internal structure, their comparatively 

 slight immersion, and darker colour of the thallus will keep ours 

 separate. 



24. V. trachona, Ach. Thallus indeterminate, thin, between 

 pulverulent and tartareous, continuous or slightly cracked, grey- 

 ish-green ; apothecia small, prominent, nearly globose, pruinose, 

 at length deformed. Borr. Eng. Bot. Supp. t.2647,f. 1. Ach. 

 Lich. Un. p. 286. 



. On rocks, near Bantry, Miss Hutchins. On rocks in Askew wood, 

 county of Kerry. I have given Mr. Borrer's specific character. There 

 are, as appears to me, two or three states of this lichen to which the 

 marks do not well apply. In one from Askew wood, the thallus is 

 more compact, and the apothecia larger, and more denuded, than re- 

 presented in Eng. Bot. In another in the same wood, and on similar 

 rocks, the thallus when moist appears to consist of very scattered 

 scales not forming a continuous surface, yet the apothecia are usually 

 quite covered with them, and appearing when dry as if varnished over. 

 In a third variety from Black water Bridge, the apothecia are so minute 

 as scarcely to be visible to the naked eye, while the thallus is more 

 pulverulent, and very like the figure in Eng. Bot. In the first of these 

 states the perithecium passes under the pale gelatinous globose, nucleus. 

 The thallus is sometimes brownish, the pruina of the apothecia ab- 

 sent. 



25. V. maura, Ach. Thallus thin, tartareous, minutely crack- 

 ed, deep brownish-black ; apothecia minute, globose, nearly 

 immersed, porous or entire at their tops. Ach. Lich. Un. p. 

 291. Eng. Bot. t. 2456. 



On maritime rocks of all kinds, common. Young thalli forming on 

 limestone are of a dark olive colour, and have a very distinct though 

 narrow whitish border. The perithecium passes beneath the nucleus, 

 which I do not find blackish as stated by Acharius but pale, of a horny 

 transparency, and gelatinous when moistened. 



26. V. umbrina, Ach. Thallus scarcely determinate, thin, 

 tartareous, minutely cracked, of an olive-black; apothecia half 

 immersed, conico-convex, papillose or porous on the summit, 

 black. Ach. Lich. Un. p. 291. Eng. Bot. t. 2499. 



On siliceous stones and rocks in the Dargle River. Acharius de- 

 fines the nucleus to be " cinerco-nigricans," or blackish-grey, but in 



