Lecidea.] 



LICHENES. H7 



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 Dunkerron. 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. ACh. 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. atru- 

 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, Ach. L. Un.p. 158, than with his «*. Disk pale brown; 

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



8. L. petrcea, 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. En j. Bot. t. 246. 



On siliceous and aluminous stones ; not uncommon. This has 



