118 LICHENES. 



[Lecidea. 



somewhat the habit of an Urceolaria, the apothecia having occasion- 

 ally a spurious border from the thallus. Beneath the dark disk is the 

 lamina proligera, of a horny transparency, pale or whitish, never of 

 the same colour as the disk, as Acharius defines it ; beneath the lamina 

 proligera is some brownish- black matter. The apothecia are com- 

 monly, but not always, concentrically arranged. 



9. L. lapicida, Ach. Thallus tartareous, thin, cracked, rather 

 smooth, grey or whitish, with a black substratum observable in 

 the interstices and at the border; apothecia half immersed, flat- 

 tish, at length somewhat confluent, black, with a narrow, raised 

 border. Ach. L. U. p. 159. Eng. Bot. t. 821. 



On siliceous and aluminous stones and rocks ; at Blackwater bridge, 

 County of Kerry ; near Belfast, Mr. Templeton. So nearly allied to 

 the preceding, that it is with the greatest hesitation here allowed to be 

 distinct. The thallus is less rough, the apothecia have not the con- 

 centric arrangement, have never the spurious border, and the entire 

 patch has at times a glaucous, and even greenish hue, not observed in 

 the preceding. Acharius relied much on the internal structure of the 

 apothecia, which I do not find to be very different : the black border, 

 indeed, is more apparent, and the disk less opaque. 



10. L. stellulata. Substratum of the thallus very thin, black, 

 exceeding at the edges; the upper layer of minute, brilliant, 

 smooth, tartareous, roundish, subcrenate scales, aggregated in 

 a subradiated manner ; apothecia central to the clusters of scales, 

 flat, black, half immersed ; the border smooth, entire, oblite- 

 rated when moist. 



On siliceous and aluminous rocks, in the Kerry mountains ; also near 

 the sea-shore : not uncommon. Patches of the thallus usually less 

 than an inch in diameter, yet sometimes confluent into such as are 

 three or four inches long. The black central apothecia are contrasted 

 with the bright white scales that surround them ; they are numerous, 

 yet evenly scattered, sometimes confluent. The white scales near the 

 border are thinner, and infertile. The patch is little or not at all al- 

 tered by moisture. The disk swells greatly when wet, and obscures 

 the border ; it is rough, but not in the least pruinose : under the lens 

 the dissected apothecium shows the disk thick and black, with black 

 converging processes entering the lamina proligera ; this is dark 

 brown, somewhat pellucid, and striated ; beneath is much black matter, 

 forming the base of the apothecium. Probably this species is alluded 

 to by Mr. Borrer under Verrucaria poli/sticta. in Eng. Bot. Supp. t. 

 2741. 



11. L. confluens, Ach. Substratum of the thallus thin, black, 

 appearing in the interstices and at the edges ; upper layer tar- 

 tareous, cracked, of a smoke-grey, even, rather smooth ; apo- 

 thecia sessile, black, pruinose, flat, at length convex and conflu- 

 ent ; the border black, raised. Ach. L. Un. p. J 74. Eng. Bot. 

 t. 1964. 



On siliceous rocks : common. Patches often several inches in dia- 

 meter. Sometimes the apothecia only, sometimes the entire thallus, 

 has a rust coloured surface ; the thallus is occasionally not observable 



