LICHENES. 95 



On siliceous rocks, occasionally inundated ; at the Dargle river, 

 County of Wicklow : faces of rocks over which water trickles at Carig 

 mountain, County of Kerry. Patches from 1 to 8 or 10 inches in 

 breadth. Thallus subtartareous, closely investing- the surface of the 

 rock, somewhat powdery on the surface when dry, slightly cracked 

 about the apothecia, swelling and becoming somewhat translu- 

 cent by moisture. Apothecia prominent, distinctly visible ; when dry, 

 appearing concolorous with the thallus ; when moistened, swelling, 

 translucent, pale-reddish, with a dark brown papillula on their sum- 

 mits, through the centre of which is a most minute pore. The peri- 

 thecium does not pass beneath the nucleus ; this is pale, gelatinous, 

 and semitransparent when moist, and exhibits a multitude of cylindra- 

 ceous vesicles fascicled together, and of different diameters, some being 

 apparently six or eight times that of others. This species seems to have ' 

 some, though but little, affinity with F. submersa. Borr. but the 

 colour and structure of the apothecia are widely different, however ap- 

 parent the similitude of their crusts. 



81. V.Jissa. Thallus tartareous, indeterminate, thin, crack- 

 ed, uneven, of a tawny dark brown, the cracks black ; apothecia 

 rather large, hemispherical, dark brown, porous, smooth, each 

 on a raised portion of the thalius. 



On large siliceous stones, occasionally inundated, in a stream at 

 Carig, County of Kerry. Thallus on being moistened becomes swell- 

 ed, of a dirty greenish-yellow colour, and somewhat gelatinous ; the 

 cracked portions resemble distinct scales, but the edges of the thallus 

 are entire, and, becoming thinner and thinner, are closely applied to 

 the subjacent surface. The thallus is sometimes stained here and there 

 blackish ; this, with the blackness of the splits, would lead to the sup- 

 position of a black substratum, but which is not to be traced more dis- 

 tinctly. Apothecia at first appear as minute black specks in the centres 

 of the areolce, pierced with a pore discoverable with a microscope : at 

 length the fertile areola swell, and form a base to each apothecium, 

 which is large as poppy seed, and has a blackish somewhat marginate 

 pore on the summit. The thallus rises very considerably about the 

 apothecia : a vertical section of the apothecia shows, under this 

 thallodal covering, a brownish perithecium, not passing beneath the 

 nucleus ; which, however, is enclosed in a transparent and colourless 

 tegument, and is itself of a pale green colour, gelatinous and hyaline. 

 This lichen has a strong affinity with the genus Endocarpon, but the 

 thallus is entirely crustaceous, not scaly. The appearances of the 

 dissected apothecia, the thicker and decidedly cracked thallus, keep 

 this species distinct from the two preceding, which likewise select 

 an aqueous situation. 



32. V. gemmifera. Thallus determinate, tartareous, powdery 

 on the surface, of a bluish-grey, with a brownish-black limit, 

 areolate, edges of the circular (soredia or) buds whitish ; apo- 

 thecia minute, half immersed, rounded or conical above, shin- 

 ing, black, dimpled. 



On siliceous rocks, Dunkerron Mountain ; not uncommon. By 

 moisture the thallus becomes greenish-grey : the fissures between the 

 areolcB are dark brown, as is the limit, which also is thicker than the 

 thallus ; hence, probably, there is a dark brown substratum : the sur- 



