LECANORA.] LECANO-LECIDEEI. 421 



Leicestershire ; Malvern Hills, Worcestershire ; Pwllheli, Carnarvon- 

 shire; Island of Anglesea; Haughmond Hill, Shropshire; Cliffrigg, 

 Cleveland, and Ribbledale, Yorkshire ; near Milnthorpe, Westmoreland ; 

 Swinhope, Northumberland ; Catterleen, Cumberland. New Galloway, 

 Kirkcudbrightshire; Kyles of Bute; Barcaldine and Ben Cruachan, 

 Argyleshire ; Killin, Perthshire ; near Dundee, Forfarshire ; Portlethen, 

 Kincardineshire ; Castleton of Braemar, Aberdeenshire. Lambay Island 

 and Kinsale, co. Cork. 



Form 1. decussata Cromb. Grevillea, xviii. (1890) p. 68. 

 Thallus white or greyish-white, finely marked throughout with 

 black hypothalline (?) lines. Apothecia as in the type, with con- 

 colorous thalliue margin. 



Looks at first sight as if almost referable to L. calcarea, but has the 

 reactions of this species. In our two British specimens the spermogones 

 are very abundant, giving the thallus a black-punctate appearance. It 

 seems to be the plant alluded to by M. Lamy, Lich. Mt. Dor. p. 75. 



Hab. On rocks in maritime and upland districts. Distr. Very spar- 

 ingly in the Clannel Islands and Is. England B. M. : Chateau Point, 

 Island of Sark. Guunerton Crags, Northumberland. 



Form 2. complanata Leight. Lich. Fl. cd. 3 (1879) p. 205. 

 Thallus and apothecia in an uniform plane, the apothecia innate. 

 Cromb. Grevillea, xviii. p. 68. 



Differs merely in the thallus and apothecia being smoothed down to the 

 same level, but is connected with the type by intermediate states, and no 

 doubt depends upon the nature of the substratum. Leighton describes 

 the apothecia as blackish; but this is accidental, and in other specimens 

 referable to this form they are of the normal colour. 



Hab. On slate-rocks in maritime districts. Distr. Only sparingly in 

 S. Wales, the W. Highlands of Scotland, and S.E. Ireland. B. M. : Near 

 Towyn, Pembrokeshire. Ballachulish, Argyleshire. Kinsale, co. Cork. 



Yar. /i.inflexa Johns, ex Cromb. Grevillea, xviii. (1890) p. 68. 

 Thallus rimoso-areolate, greyish-white. Apothecia plane, crowded ; 

 the thalline margin prominent, thickibh, snow-white, crenate and 

 flexuose. 



A distinct variety characterized by the thalline margin of the apothecia. 

 These are for the most part aggregate and become angulose through 

 mutual pressure. It is scarcely referable to var. ruyosa (Ach.) Fr. til. 

 Lich. Scand. p. 271. 



Hah. On quartzose rocks in an upland district. Distr. Very local in 

 N.W. England. B. M. : Alston, Cumberland. 



Var. y. Swartzii Nyl. Lich. Scand. (1861) p. 159. Thallus un- 

 equal, rimose or verrucoso-granulate, subradiate or at times byssino- 

 radiate at the circumference. Apothecia subglobose, usually aggre- 

 gato- conglomerate, the thalline margin at length evanescent. 

 Cromb. Lich. Brit. p. 50 ; Leight. Lich. Fl. p. 216, ed. 3, p. 205. 



