Lecidea.] LICHENES. 117 



covering a pale, almost white, thin lamina proligera, beneath which 

 again is much brownish-black matter, completing the rest of the apo- 

 thecium. Minute tumours of the scales, irregularly opening, with 

 white powdery edges, black within, constitute the buds. 



5. L. recedens. Substratum of the thallas subtartareous, 

 thick, black, cracked ; the scales of a smoke-grey ; the infertile 

 thin, minute, crowded ; the fertile large, roundish, somewhat 

 lobed ; apothecia immersed, scattered, flat; disk black; the 

 border paler, obliterated by moisture. 



On siliceous rocks, mountains near lJunkerron. The situation of 

 the apothecia is like that of the preceding, viz. on the scales of the 

 thallus ; these are somewhat browner when wet ; the infertile are 

 crowded into an areolate form. The apothecia, concave when dry, be- 

 come plane when saturated with moisture : the border sometimes ap- 

 pears to have a whitish pruina : when dissected the disk appears thin, 

 and rough, with projecting black points ; the lamina proligera is thick, 

 striated, nearly colourless, transparent, resting on dark brown matter. 

 The species is allied to Urceolaria cinerea. 



6. L. fusco-atra, ACH. Substratum of the thallus black, 

 thin ; scales greyish-black, crowded into an areolate form, flat, 

 pruinose ; apothecia larger than the scales, slightly immersed in 

 the interstices, depressed ; the disk flat, black, rather rough ; 

 the border paler, thick, raised. A h. L. Un.p. 359. Eng. Bot. 

 t. 1734. 



On flints, near Belfast, Mr. Templeton. The border to the thallus 

 is a radiating production of the substratum. The surface of the older 

 apothecia is sometimes proliferous and rough with young apothecia. 

 Dissection shows the disk black and opaque, covering a thin, semi- 

 transparent lamina proligera, resting on brownish-black matter. 

 It is difficult, perhaps impossible, to distinguish this from L. atro~ 

 alba. 



7. L. cechumena, ACH. Substratum of the thallus thin, black, 

 appearing among the interstices and at the edges ; upper layer 

 of tartareous, tumid warts crowded and confluent at the centre, 

 distinct at the edges, powdery, white on the surface, under 

 which of a pale, brownish-olive ; apothecia on the warts, im- 

 mersed, blackish, at length convex ; the border thin, partially 

 covered with a thallodal layer. Ach. Meth. p. 42. Eng. Bot. t. 

 1830. 



On siliceous rocks, near Dunkerron, County of Kerry. Our plant 

 agrees better with the description of the variety |3. athroocarpa of L. 

 cechumena, Adi. L. Un.p. 158, than with his . Disk pale brown ; 

 lamina thick, nearly colourless, striated, resting on brown matter. 



8. L. petr&a, ACH. Thallus thin, tartareous, suborbicular, 

 whitish, cracked, minutely warted; with a black substratum 

 observable in the interstices, and at the border ; apothecia im- 

 mersed, black, flat, with an elevated, tumid border. Ach. L. 

 Un. p. 155. Enj. Bot. t. 246. 



On siliceous ant! aluminous stones ; not uncommon. This has 



