420 LICQENACEI. [LECANORA. 



Killin, Perthshire. Near Belfast, co. Antrim ; Castleconnell, co. Limerick ; 

 Killaloe, co. Clare. 



Var. /3. chondrotypa Stiz. Bot. Zeit. 1868, p. 899. Thallus as in 

 the type. Apothecia convex, often crowded, whitish or subcarneous, 

 the thalline margin excluded. Cromb. Grevillea, xviii. p, 68. 

 Lecanora chondrotypa Ach. Lich. Univ. (1810) p. 365. According 

 to Nylander (Lich. Scand. p. 162) this is present in Hb. Acharius 

 s. n. Lichen glabratus Dicks., but as Dickson does not record it his 

 specific name cannot be retained. 



Differs in the character of the apothecia, which, however, in a very 

 young state are plane with a distinct thalline margin. 



Hab. On the trunks of trees in wooded upland tracts. Distr. Local 

 and scarce in S. England. B. M. : Bembridge, Isle of Wight ; St. Leo- 

 nard's Forest, Sussex ; Lyndhurst, New Forest, Hants ; Ullacomhe, Bovey 

 Tracey, S. Devon. 



100. L. glaucoma Ach. Lich. Univ. (1810) p. 362. Thallus sub- 

 determinate, at first continuous, then rimoso-areolate, whitish or 

 glaucous- white (K + yellow, CaCl ); hypothallus thin, whitish. 

 Apothecia moderate, innate or appressed, plane or convex, carneous- 

 livid or livid-black, caesio-pruinose (CaCl -f- yellow) ; the thalline 

 margin thin or tumid, at length flexuose and obliterated ; spores 

 ellipsoid, 0,010-13 mm. long, 0,006-7 mm. thick : paraphyses 

 somewhat slender, conglutinate ; hymenial gelatine deep blue, the 

 theca? violet with iodine. Hook. Fl. Scot. ii. p. 48 ; Sm. Eng. Fl. 

 v. p. 189 ; Tayl. in Mack. Fl. Hib. ii. p. 135 ; Mudd, Man. p. 153 ; 

 Cromb. Lich. Brit. p. 50 ; Lcight. Lich. Fl. p. 215, ed. 3, p. 204. 

 Rinodina glaucoma Gray, Nat. Arr. i. p. 453. Lichen glaucoma 

 Eng. Bot. t. 2156. Verrucaria glaucoma Hoffm. Deutsch. Fl. ii. 

 (1795) p. 172. Lichen rupicola (? Linn.) Lightf. Fl. Scot. ii. p. 806 ; 

 Huds. Fl. Angl. ed. 2, p. 525 ; With. Arr. ed. 3, iv. p. 13. Brit. 

 Exs. : Leight. n. 53 ; Mudd, u. 122 ; Larb. Lich. Hb. n. 259. 



A very variable plant as to the thallus and apothecia, whence the forms, 

 varieties, and subspecies that foil w. It may, however, always be easily 

 recognized by the livid-pruinose apothecia. The thallus, which is rarely 

 caesio-greyish, is thickish, more or less expanded, the hypothallus being 

 visible only in shaded situations at the circumference. It is usually well 

 fertile, the apothecia being numerous (at times aggrega to-conglomerate), 

 with the pruina persistent (forma cinereopruinosa Leight. Lich. Fl. p. 216) 

 unless when accidentally rubbed off. The spermogones are frequent, 

 black-punctate, immersed, with spermatia arcuate, as in the allied species. 

 Both the thallus and the apothecia are the hosts respectively of two dif- 

 ferent parasites hereafter to be described. 



Hab. On rocks, boulders, and walls, granitic, schistose, and whinstone, 

 in maritime and upland situations, chiefly in mountainous districts. 

 Distr. General and common in Great Britain ; no doubt also in Ireland. 

 B. M. : La Moye, Island of Jersey ; The Vale, Guernsey ; Island of 

 Sark. Near Folkestone, Kent; Bolt'Head, S. Devon; Valley of Rocks, 

 Lynton, N. Devon ; St. Minver and Penzance, Cornwall ; Bardon Hill, 



