462 LICHEXACEI. [lECANOEA. 



Form 1. crenularia Cromb. Grevillea, xviii. (1890) p. 70. 

 Thallus as in the type. Apothecia with the thalline margin rugoso- 

 crenulate. 



Differs merely in the coarsely crenulate thalline margin of the apothecia, 

 which, however, is occasionally less distinctly visible in their juve 



juvenile 

 state, so that it is scarcely a variety. 



Hub. On rocks and trunks of old trees in maritime and upland 

 situations. Distr. Only a very few localities in Great Britain and 

 Ireland. B. M. : New Forest, Hants ; Hale's End, Malvern, Worcester- 

 shire ; Wansbeck Valley, Northumberland. Island of Lismore, Argyle- 

 .shire. Brandon mt., co. Kerry. 



Form 2. nivea Cromb. Thallus and the thalliue margin of the 

 apothecia soft, snowy-white ; otherwise as in the type. 



Apparently a well-marked form, which, if the characters given are 

 constant, would be a good variety. In the two small British specimens 

 the thallus is verrucoso-rugose and the apothecia concave with thick 

 thalline margin. 



Hab. On the trunk of an old tree in an upland situation. Distr. Seen 

 only very sparingly from W. Ireland. B. M. : Killaloe, co. Clare. 



Var. /3. Turner! Nyl. Mem. Soc. Cherb. v. (1857) p. 113.^ 

 Thallus more or less leproso-dissolved, whitish or greenish-white. 

 Apothecia submoderate, white-pruinose ; the thalline margin thick, 

 entire, white-pulverulent. Cromb. Lich. Brit. p. 54 ; forma Turneri 

 Leight. Lich. Fl. p. 190, ed. 3, p. 203. L. pallescens y. Turneri 

 Mudd, Man. p. 155. Rinodina Turneri Gray, Nat. Arr. i. p. 454. 

 Lecanora Turneri Sm. Eug. Fl. v. p. 191. Lichen Turneri Eng. Bot. 

 t. 851. Brit. Exs. : Mudd. n. 127; Leight. n. 237. 



A good variety characterized by the white-sorediate thallus and the 

 pulverulent margin of the apothecia. These are usually rather scattered, 

 with the thalline margin rarely subcrenulate (form subcrenata Cromb. 

 Grevillea, xviii. p. 70). 



Hab. On trunks of old trees in maritime and upland wooded regions. 

 Distr. Here and there throughout England ; rare in N. Wales, the 

 S.W. Highlands and N. Grampians, Scotland, as also in S. Ireland. 

 B. M. : Epping Forest, Essex ; The Holmwood, Surrey ; Hurstpierpoint, 

 Sussex; Carrisbrook and Bembridge, Isle of Wight; New Forest, 

 Hampshire ; Gillingham, Dorsetshire ; Ugbrook Park, Chudleigh, S. 

 Devon; Savernake Forest, Wiltshire; near Barmouth, Merionethshire; 

 near Ayton, Cleveland, Yorkshire ; Egleston, Durham. By Loch Creran, 

 Barcaldine, Argyleshire ; Morrone, Braemar, Aberdeenshire. Old Deer 

 Park, Castlemartyr, co. Cork ; Muckruss, Killarney, co. Kerry. 



156. L. pallescens Nyl. Bull. Soc. Linn. Normand. ser. 2, t. ii. 

 (1868) p. 68. Thallus determinate, thinnish, granulato-unequal, 

 whitish or greyish- white (K , CaCl ) ; hypothallus white, limiting 

 the thallus. Apothecia submoderate, concave or somewhat plane, 



