264 CYCLOCARPINEE [LECANORA 
covered by the apothecia which become irregular from pressure ; 
sometimes the squamules are white-margined in part, or over the 
whole thallus (subsp. albomarginata). 
Hab. On rocks, boulders, walls, etc., rarely on oak palings in 
maritime and inland districts.—Distr. General though not common 
throughout the British Isles.—B. M. Fliquet Bay, Jersey; Vale 
Castle, Guernsey; Sark; near Penzance, Cornwall; near Ryde, I. of 
Wight; near Lewes and Midhurst, Sussex; Penshurst, Kent; near 
London, Middlesex; Chelmsford, Essex; Yarmouth, Norfolk; Bed- 
fordshire; Ross, Herefordshire; Malvern Hills, Worcestershire ; 
Bridge of Ludlow, Haughmond Hill, Oswestry and Caer Caradoc, 
Shropshire; Twycross, Leicestershire; Dolgelly, Barmouth and 
Cader Idris, Merioneth; Llandyssil, Cardiganshire; Anglesea; Cliff- 
rigg, Cleveland, Yorkshire ; near Egglestone and Teesdale, Durham ; 
near Kendal and Brougham Castle, Westmoreland; Wark and 
Gunnerton Crags, Northumberland ; New Galloway, Kirkcudbright- 
shire; Arthur’s Seat and Dalmahoy Hill, Edinburgh; Kyles of Bute ; 
Burntisland, Fifeshire; near Connel Ferry, Argyll; Ben Lawers, 
Perthshire; Castleton of Braemar, Aberdeenshire; Kileully near 
Cork; near Belfast, Antrim. 
Var. diffracta Scher. 1. c.—Thallus almost entirely cartila- 
ginous-areolate, greyish-green or generally dark-coloured. 
Apothecia dark-reddish, with lighter thin disappearing margins. 
—L. saxicola var. diffracta Cromb. in Grevillea xviii. p. 44 
(1889) & Monogr. i. p. 354. Lichen diffractus Ach. Lich. Suec. 
Prodr. p. 63 (1798). Squamaria saxicola var. diffracta Nyl. 
Lich. Scand. p. 133 (1861) ; Cromb. Lich. Brit. p. 45; Leight. 
Lich. Fl. p. 173; ed. 3, p. 159. Var. areolata Leight. ex Mudd 
Man. p. 129 (1861). 
Exsicc. Leight. n. 81; Mudd n, 93. 
The squamulose character is generally obscure, though the plant 
is occasionally lobate at the circumference. 
Hab. On rocks in upland and subalpine situations.—Distr. Local 
and scarce in England and the Grampians, Scotland.—B. M. St. 
Minver, Cornwall; Haughmond Hill, Shropshire ; near Ayton, Cleve- 
land, Yorkshire; Ben Lawers, Perthshire; Craig Guie, Braemar, 
Aberdeenshire. 
Var. versicolor Tuckerm. Syn. N. Amer. Lich. p. 185 (1882). 
—Thallus generally reduced, light-coloured, white-suffused. 
Apothecia with prominent white crenulate margins.—L. saxicola 
var. versicolor Cromb. in Grevillea xviii. p. 44 (1889) & Monogr. 
i. p. 354 (incl. f. dispersa). Lichen versicolor Pers. in Ust. Ann. 
Bot. vii. p. 24 (1794). Squamaria saxicola var. versicolor Nyl. 
Lich. Scand. p. 133 (1861); Leight. Lich. Fl. p. 174; ed. 3, 
p- 159 (inel. var. albomarginata f, dispersa). 
Ezxsice. Johns. nu. 311. 
The thallus may be very reduced and the apothecia scattered or 
united in pulvinate groups (f. dispersa). The powdery-white appear- 
ance is most characteristic in the prominent thalline margins of the 
apothecia. 
