Lecidea.} LICHENES. 115 



gelatinous, semi-transparent, sub-rotund, not enclosed in any distinct 

 tegument, containing elongated cellules in a jelly-like substance. 



11. V.terricola. Thallus thin, pulverulento-tartareous, white, 

 rough, indeterminate, continuous; apolhecia globose, with a 

 thin, white, granulate, covering; disk pale flesh-coloured ; bor- 

 der irregular. 



On the surface of peat and on stems of heath near Comber, Mr. 

 Tcmpleton. Dunkerron Mountain : rare. The patches are several 

 inches broad. The thallus has a rugged appearance, principally arising 

 from the cup-shaped remains out of which the apothecia have dropped. 

 Apothecia sometimes a little flattened, sometimes elongated ; their 

 granulated and wrinkled covering on dissection shows a layer of green 

 parenchymatous matter, proving its nature to be thallodal. The 

 moistened lamina proliyera contains numerous pellucid globular 

 bodies. At some little distance the patch may be passed over as be- 

 longing to Cenomyce Pycnothelia, or, perhaps, to that of Lecidea 

 icmadophila, both of which affect similar situations ; but the slightest 

 examination of the apothecia would suffice to correct either error. 



22. Lecidea, AcJi. 



Thallus crustaceous, uniform, or scaly, apothecia orbiculate, 

 sessile, or slightly immersed ; the disk, coloured ; the border 

 of the same colour as the disk. 



f Thallus crustaceous. 



* Apothecia black. 



1. L. macula. Thallus subtartareous, very thin, determinate, 

 areolate, inferior stratum black ; upper of very minute, dis- 

 tinct, crowded, thin, greyish-olive, concave scales ; apothecia 

 half immersed, concave ; the disk black, rough ; the border 

 elevated, pale when dry. 



On siliceous rocks, near Dunkerron, County of Kerry ; not uncom- 

 mon. The patches, one or two inches in diameter, closely invest the 

 surface of the rock, and are conspicuous as black stains. The thallus, 

 though extremely thin, is composed of two layers, of which the inferior 

 is most abundant, black, seen between the minute scales, of which the 

 superior is composed, and likewise exceeding at the edges. The scales 

 are- concave, of a greyish olive, roundish or oblong, with elevated 

 whitish edges observable only by the lens ; in a dry state their surface 

 is rough and somewhat powdery. The apothecia, thinly scattered and 

 inconspicuous to the naked eye, are immersed in the scales, and have a 

 pale, entire, raised border, of the colour of the scales when dry, but 

 black when wet ; the disk by moisture swells, becomes convex ; it is 

 black ; beneath which, dissection shows the lamina proligera to be a 

 thin layer, pale brown and semi-transparent. This species, perhaps, 

 may with equal propriety be referred to the genus Urceolaria but 

 for its great affinity to a small tribe allied to Lecidea atro-alba. 



2. L. melastigma. Thallus subtartareous, very thin, subdeter- 

 minate, areolate, inferior stratum black ; upper of very minute, 



