CRCEOLARIA.] LECAXO-LECIDEEI. 517 



Hub. On rocks and walls, very rarely on old wood, from maritime to 

 subalpine districts. Distr. General and common in Great Britain; ap- 

 parently rare in the Channel Islands aud in Ireland, though plentiful 

 where "it occurs. B. M. : Island of Guernsey. Livermere, Suffolk ; 

 Walthamstow, Essex ; Kew Gardens, Surrey ; Barton Mills, Sussex ; 

 near Shanklin, Isle of Wight; Lustleigh, S. Devon; near Padstow, 

 Cornwall ; Bathampton Downs, Somerset ; Ampthill, Bedfordshire ; 

 Goguiagog Hill and Chevely Park, Cambridgeshire ; near Buxton, Derby- 

 shire ; Bardon Hill, Leicestershire ; Cader Idris and Baruiouth, Merio- 

 nethshire ; Island of Auglesea ; Oswestry, Gruishill, near Shrewsbury, 

 aud High Rock, Bridgenorth, Shropshire ; Lounsdale, Cleveland, York- 

 shire ; Teesdale, Durham ; Staveley, Westmoreland ; Chesters, North- 

 umberland ; Alston, Cumberland. 'New Galloway, Kirkcudbrightshire ; 

 King's Park and Craig Lockhart, Edinburgh ; West Water, Fifeshire ; 

 Appin, Argyleshire ; Den of Mains, Forfarshire ; Ben Vrackie and near 

 Dunkeld, Perthshire ; Morrone, Braemar, Aberdeenshire ; near Fort 

 William, Inverness-shire. Kilcully, co. Cork ; Loughcooter, co. Galway. 



Form plumbea Ach. Heth. (1803) p. 147. Thallus greyish- 

 leaden-coloured. Apothecia usually small and naked ; otherwise as 

 iu the type. 



Characterized chiefly by the darker thallus, which is probably owing 

 to the nature of the substratum. 



Hab. On calcareous and cretaceous soil in maritime and upland 

 situation.*. Distr. Apparently local and scarce in S. and Central Eng- 

 land and the S.W. Highlands of Scotland. B. M. : Near Hoathly, 

 Sussex ; Buxton, Derbyshire. Island of Lismore, Argyleshire. 



Subsp. II. bryophila Xyl. ex STorrl. Medd. Siillsk. pro F. et Fl. 

 Fenu. i. (1876) p. '27. Thallus thinner, smoother, or less rugose, 

 greyish-\\hite or whitish, often obsolete or scarcely visible. Apo- 

 theciu smaller, the thalline margin subevanescent ; otherwise as in 

 the type. Cromb. Grevillea, xix. p. 60. U. scruposa var. bri/o- 

 pTiila Mudd, "Man. p. 165; Cromb. Lich. Brit. p. 50 ; forma, Leight. 

 Lich. Fl. p. 235, ed. 3, p. 240. Lichen brijophilus Ehrh. Exs. 

 (1785) n. 236. Brit. Exs. : Leight. nos. 359, 360 ; Larb. Lich. Hb. 

 nos. 63, 221. 



A good subspecies distinguished by the characters given. The thallus, 

 which is usually somewhat effuse, is at times somewhat dealbate and 

 subpulverulent, when it is var. /3. dealbata Ach. Lich. Univ. p. 341. It 

 often grows upon the folioles and the podetia of forms of Cludonia 

 jn/xidata either as a parasite or with scanty traces of a proper thallus, 

 and it is then Lecanora scruposa j3. parasitica Somm. Suppl. Fl. Lap. 

 p. 100 pro parte, form ecrustacea Nyl. Cromb. Grevillea, xix. p. 60. This 

 condition, however, is scarcely entitled to rank even as a form. 



Hab. Overspreading mosses and on Cladonia pyxidata in maritime 

 and upland tracts. Distr. Not uncommon, in Great Britain and Ireland ; 



rare in the Channel Islands. B. M. : Queuvais, Island of Jersey. 



Thetford Warren, Norfolk ; Eppiua: Forest, Essex ; near Torquay and 

 on Lustleigh Cleeve, S. Devon ; St. Minver and Penzanoe, Cornwall ; 

 Pembury Park, Cirencester, Gloucestershire ; Matlock, Derbyshire ; 

 Dolgelly and Barmouth, Merioneth ; High Rock, Bridgenorth, Shrop- 

 shire ; Lanbraugh, Cleveland, Yorkshire ; Eglestone, Durham. Island 

 of Lismore and Appin, Argvleshire ; Glen Lochay, Killin, Ben Lawers, 



