Cottema.} LICHENES. 109 



the branches radiating, the ultimate subcrenate, convex above, 

 concave beneath ; apothecia sessile, at length convex, the disk 

 brownish or black, the border nearly entire. Eng. Bot. t. 2582. 

 P. fluviatile, segments obovate, nearly entire; apothecia glo- 

 bose, concave. Ach. L. Un. p. 636. Eng. Bot. t. 2039. 



. on limestone, in dry situations, at Dunkerron ; common. (3. on 

 limestone in rivulets at Sallagh Braes, County of Antrim, Mr. Tem- 

 pleton. The lichens that grow absolutely in water are few, if any. I 

 have referred C. fluviatile (at least of Eng. Bot.) as a variety arising 

 from occasional inundation, to C. multipartitum, (of the same work.) 

 The thallus of both is sometimes granulated with buds. I do not 

 think any specific distinction is discoverable to keep the two sepa- 

 rate. 



8. C. fragile. Thallus orbicular, olive-black, radiating, at 

 length open in the centre, marginal lobes rough with wrinkles 

 and granules, concave beneath ; apothecia immersed, concave, 

 their disk pale tawny ; their border scarcely raised above the 

 thallus. 



On limestone rocks ; at Dunkerron, County of Kerry. Thallus in 

 round patches from three to four inches in diameter, divided into ra- 

 diating lobes, the central parts at length deficient, or the plant increas- 

 ing by a prolongation at the circumference, in which case the lobes are 

 quite unconnected. The lobes are short, linear, tumid, deflexed at the 

 top, concave beneath, scarcely crenate, sooty-black inclining to greenish- 

 olive, sometimes to brown when dry ; by moisture becoming of a dark 

 olive-green and more pellucid ; their upper surface rough with granules, 

 concolorous with the thallus, clustered, of different sizes, globular, yet 

 flattened at the top ; the newer and circumferential portions of the 

 thallus are often a little wrinkled above. Apothecia on lobes that are 

 thicker and paler than the barren, clustered, quite immersed, the disk 

 very pale brown ; they occur but rarely, and when present are not 

 easily seized by the eye. This species has so strong an affinity to the 

 preceding that it probably has been taken for young patches of it. 

 But, although usually growing in company with, it is scarcely one-sixth 

 of the size of C. multipartitum ; and no intermediate states are to be 

 found. It is of a darker colour, its surface more rough, but, above all, 

 the full grown apothecia are so minute as to be inconspicuous to the 

 naked eye, entirely plunged in the thallus and very pale. The re- 

 peated observation of numerous specimens gave the same results. 



9. C.marginale, HOOK. Thallus orbicular, olive-black, sub- 

 stellate, the lobes imbricated, deeply laciniated, multifid, flexu- 

 ose, sessile, dark reddish-brown, their border at length entire. 

 Hook. Eng. Flor. v.5,p. 210. C. melcenum. p. marginale, Ach. 

 L. U. p. 637. Eng. Bot. t. 1924. 



Near Belfast, Mr. Templeton ; near Bantry, Miss Hutchins. The 

 border to the shields appears sub-crenulate, owing to the granular buds 

 of the thallus that are affixed to the outside of the apothecia ; when 

 these buds at length drop off, the border remains entire. 



