Par nulla. 



LICHENES. 145 



Apothecia concave, substipitate, exteriorly rough with buds. 

 Ach. Meth. Lich. p. 2-54. Eng. Bot. t. 984. Borrera farfuracea. 

 Ach. L. Un. p. 500. Eng. Hook. FL v. 5, p. 223. 



On granite, also on old trees at Lough Bray, near Dublin. 



4. Buds, powdery, on linear eruptions of the thallus. 



14. P. sulcata. Thallus orbicular, stellate, glaucous white 

 when dry, glaucous green when wet, dark brown, with black 

 fibres beneath, the lobes incised, somewhat concave, reticulated 

 with elevated ridges ; buds in oblong or linear eruptions, con- 

 sisting of a greyish-brown fine powder. Apothecia central, 

 substipitate ; the disk brown ; the exterior smooth, or with 

 powdery buds. Lich. saxatilis, Scop. FL Corn. II. p. 383. Jacq. 

 Collect, torn. IV. t. 20, /. 2. 



On siliceous rocks, also on trees ; not uncommon. This species far 

 more common on rocks in the County of Kerry than on trees, attains 

 a foot or more in diameter : it is proposed as distinct from P. saxatilis, 

 as bein<* larger, whiter, its segments less imbricated, more concave, 

 more green when wet, the buds powdery, not stipitate, and conse- 

 quently the backs of the apothecia far more smooth. Mr. Borrer in- 

 forms me that in the list of Tunbridge Plants by Mr. Foster, it has 

 been called P. conspersa, for which it was mistaken. 



15. P. rugosa. Thallus very uneven, white, unaltered when 

 wet; lobes broadly linear, imbricated, rugose at the base; buds 

 in a grey powder along the tops of the ruptured ragce; apothecia 

 smooth, the margin crenate. 



On heath in large tufts ; also on rocks, with apothecia on the banks 

 of Blackwater River, County of Kerry. Patches often a foot or more 

 in diameter, attractive by their whiteness ; the surface extremely 

 uneven : the lobes are divaricating, linear though broad, their extremi- 

 ties oftener retuse than rounded, their sinuses somewhat oval. The 

 more aged portions of the thallus above are closely wrinkled : the tops 

 of the wrinkles sometimes appear abraded, and show a tine, pale ash- 

 coloured powder ; often, however, they are scarcely split above when 

 the edges of the dark cracks exhibit minute, white, rotund or fiat disks 

 that soon assume the appearance of fronds. The apothecia are smooth 

 exteriorly, except the very aged, on the backs of which buds may be 

 observed" with a lens. The nature of the buds, the linear lobes, and 

 uneven surface of the frond, with their singularly wrinkled surface, dis- 

 tinguish this from P. lavigata, Ach. with which it may be easily con- 

 founded. 



16. P. omph'alodes, Ach. Thallus substellate, purplish- 

 brown, shining, rough with dark points, black and fibrous be- 

 neath ; the segments linear, flat, sinuato-multifid, subtruncate ; 

 the buds in a fine white powder in linear elevations of the 

 thallus. Apothecia substipitate, concave ; the disk brown ; the 

 border thin, incurved. Ach. L. Un. p. 469. Eng. Bot. t. 

 604. 



On rocks in the mountains ; common. Varies in the breadth of the 



s 



