384 LJOHENACEI. [LECANORA. 



Argyleshire ; Ben Lawers, Perthshire ; Rothiemurchus and near Fort 

 William, Inverness-shire. Ballyuahinch, Connemara, co. Galway ; 

 Westport, co. Mayo. 



Form submersa Nyl. Flora, 1885, p. 43. Thallus thin, dark, at 

 length rimuloso-diffract ; otherwise as in the type. Cromb. 

 Grevillea, xviii. p. 46. 



Differs merely in the character of the thallus, which is probably owing 

 to the habitat. T have not seen a British specimen. 



Hab. On stones in streams in upland situations. Distr. Very sparingly 

 in N.W. Ireland (near Kylemore, Connemara, co. Galway). 



Var. /5. pyrithroma Nyl. Bull. Soc. Bot. t. xiii. (1866) p. 367. 

 Thallus paler, often scarcely visible. Apothecia somewhat convex, 

 deep-yellow or reddish ; spores 0,010-13 mm. long, 0,004-6 mm. 

 thick. Cromb. Grevillea, xviii. p. 46 ; Lich. Brit. p. 47. Lecidea 

 rupestris p. pyrilhroma Ach. Lich. Univ. (1810) p. 206. Brit. 

 Exs. : Larb. Lich. Hb. n. 335. 



Differs chiefly in the size of the spores. It usually occurs athalline and 

 mixed up with other crustaceous lichens, so that it is apt to be over- 

 looked. 



Hab. On rocks, walls, and flints in lowland and upland tracts. Distr. 

 Seen from only a few localities in Great Britain and N.W. Ireland. 

 B. M. : Thetford Warren, Norfolk ; Kildale, Cleveland, Yorkshire. 

 Craig Tulloch, Blair Athole, Perthshire ; Park, near Aberdeen ; Craig 

 Guie, Braemar, Aberdeenshire. Lough Inagh, Connemara, co. Galway. 



Form picta Cromb. Grevillea, xviii. (1889) p. 47. Thallus thin, 

 greyisb, evanescent. Apothecia concave, then plane, pale greenish- 

 dun coloured, yellow-pruinose, the proper margin thickish, inflexed. 

 Lecidea picta Tayl. in Mack. Fl. Hib. ii. (1836) p. 130. Leca- 

 nora pyracea var. pyriihroma Leight. Lich. Fl. p. 222, ed. 3, 

 p. 212. Brit. Exs. : Larb. Lich. Hb. n. 55. 



Only a form of var. 8, distinguished chiefly by the bright-yellow 

 pruina -with which the fruit is covered. In specimens long preserved 

 in Herbaria this disappears. The apothecia are minute or somewhat 

 small, numerous and usually crowded. 



Hab. On schistose rocks in mountainous regions. Distr. Local and 

 scarce on the S. Scottish Grampians and in W. Ireland. B. M. : Ben 

 Lawers and Craig Calliach, Perthshire. Carig Mt., co. Kerry ; Lettermore, 

 Connemara, co. Galway. 



Var. y . lactea Stiz. St. Gall. Nat. Ges. 1881, p. 352. Thallus 

 thinnish, amylaceous, chalky- white. Apothecia small, orange-red, at 

 length convex and immarginate. Cromb. Grevillea, xix. p. 60. 

 Callopisma luteo-album var. lacteum Mass. Sched. Grit. (1855) 

 p. 133. 



A good variety characterized by the colour of the thallus and of the 

 apothecia. Massalongo, I. c., describes the latter as scattered ; but, in the 

 specimens seen, they are here and there congregate. It is a very doubtful 



