Lecidea.] LICHENES. 131 



61. L. cceruleo-nigricans. Thallus of imbricated, tumid, 

 obovate, pruinose scales, entire or crenate ; apothecia marginal, 

 black, at length convex and waved ; the border narrow. Lichen 

 cceruleo-nigricans^ Light. Eng. Bot. t. 1139. Psora ceruleo- 

 nigricans, Hook. Eng. Flor. v. 5, p. 192. Lecidea vesicularis, 

 Ach. L. Un p. 212. 



On the North Wall, near Dublin, Mr. Robert Brown. At the 

 sand hills of Baldoyle, near Dublin, abundant. &. aromatica, scales 

 rather erect, fastigiate, of a brownish-grey, somewhat pruinose. 

 Lecidea aromatica, Hook. Eng. Flor. v. 5, p. 177. Lichen aro- 

 maticus Eng. Bot. t. 1777. On walls, at Dunkerron Castle ; on wet 

 rocks in the mountains near Dunkerron. Sir James Smith, long since, 

 affirmed the difficulty of separating what are above united into varie- 

 ties : the propriety of which is strongly indicated by the identity of 

 the remarkable odour that issues from the bruised recent apothecia 

 of both, the scent being that of Geranium robertianum, though 

 fainter. 



62. L. polytropa^ ACH. Thallus in dispersed clusters of 

 tumid, wrinkled, somewhat lobed, pale, sulphur coloured, tar- 

 tareous scales ; apothecia conglomerate, plane or convex ; their 

 disk of a pale flesh colour ; the border lighter, waved, and cre- 

 nate. Ach. Method. Lich. p. 72. Eng. Bot. t. 1264, the lower 



figure. 



On siliceous rocks, at Derriquin, County of Kerry. In our plant 

 a black, powdery substratum to the thallus is observable, which I do 

 not find in specimens from Ben. Lawers, collected by the late Mr. J. 

 Mackay ; besides, the scales of our plant are in distinct swolu 

 clusters, which is not represented in the English Botany plate. 



63. L. fuliginosa. Substratum of the thallus of numerous, 

 short, fastigiate, simple or branched, bent filaments, black as 

 their connecting thin membrane ; scales minute, much scatter- 

 ed, flat, hemispherical, entire, of a dusky olive ; apothecia black, 

 convex, the border soon obliterated. 



On siliceous slate at Dunkerron and Carig mountains, County of 

 Kerry. Patches, at a little distance, appear like the rudiments of An- 

 drcBa Rothii ; from one to four inches in diameter. The filaments of 

 the substratum when dry are black, when wet of a light brown ; they 

 are especially collected about the circumferences of the scales, and of 

 the apothecia, to which they adhere ; towards the margin of the patch 

 they are short. The scales, larger than poppy seed, are commonly 

 distinct, sometimes confluent, when wet they are almost gelatinous, 

 otherwise they remind one of the scales of an Endocarpon : when 

 cut, under the lens, they exhibit beneath a brown, semi-transparent, 

 cortical layer, another more thick, quite green when wet, resting on 

 much cortical matter, whose whiteness, as usual, is not altered by mois- 

 ture. The apothecia are often subglobose, somewhat shining, situated 

 single or two together on one of the scales, overhanging its side. Dis- 

 section shows the disk thin and black ; the lamina proligera of a 

 light brown, pellucid, striated, in a very thin layer; while the centre 

 and greater part of the apothecium is occupied by much black matter, 

 which occasionally protrudes, from beneath, beyond the base of the 

 apothecium. 



