500 1ICHENACEI. [PERTUSAEIA. 



Barcaldine, Argyleshire ; Glen Lochay, S. of Loch Tay, Killin and 

 Balthayock Woods, near Perth, Perthshire ; Countesswells Woods near 

 Aberdeen, and Craig Cluny, Braemar, Aberdeenshire; near Fort William, 

 Inverness-shire; Lairg, Sutherlandshire ; Applecross, Ross-shire. Blarney, 

 co. Cork ; Dunkerron, co. Kerry. 



Form rupestris DC. El. Fr. ii. (1805) p. 320 ; Nyl. Flora, 1881, 

 p. 456. Fertile verrucae more or less aggregato-difform, verrucoso- 

 areolate ; otherwise as in the type. Cromb. Lich. Brit. p. 59 (excl. 

 syn.) ; Leight. Lich. Fl. p. 239, ed. 3, p. 23Q.Pertusaria rupestris 

 Mudd, Man. p. 272. Var. (3. areolata Mudd (non Clem.), 1. c., is 

 merely a darker state. Brit. Eocs. : Mudd, n. 259. 



Only a saxicolous condition of the type, from which it scarcely differs 

 except in the thallus being usually more verrueose. 



Hub. On rocks in maritime and upland districts. Distr. Only 

 sparingly in S. and N. England and the S.W. Highlands of Scotland. 

 B. M. : Hastings, Sussex : Aytou, Cleveland, Yorkshire ; near White- 

 haven, Cumberland; Island of Lismore, Argyleshire; Aberfoyle, 

 Perthshire. 



Subsp. P. areolata Nyl. ex Hue, Rev. Bot. 1886, p. 74. 

 Thallus thickish, rimoso-areolate, rugose, shortly and more or less 

 densely papillate, greyish-white (K + yellow). Apotbecia as in 

 the type. Pertusaria areolata Nyl. Flora, 1881, p. 456; Cromb. 

 Grevillea, xix. p. 59. Thelotrema pertusum var. areolatum Clem. 

 Ens. &c. Add. (1807) p. 300. 



Often confounded with the preceding form, but differs in the character 

 of the thallus and in the reactions. As Nylander says, it may be a 

 distinct species. In the British specimens only a few scattered apothecia, 

 not well developed, are present. 



Hab. On rocks and walls, schistose and arenaceous, in mountainous 

 districts. Distr. Local among the Grampians and in the N. W. Highlands 

 of Scotland. B. M. : Craig Calliach and Craig Tulloch, Blair Athole, 

 Perthshire ; Morrone, Braemar, Aberdeenshire ; Hills of Applecross, 

 Ross-shire. 



14. P. dealbata Nyl. ex Cromb. Lich. Brit. (1870) p. 59 (excl. 

 syn. P. lactescens) ; Flora, 1880, p. 390. Thallus subindetermi- 

 nate, grauuloso-unequal or papillose, rimose or diffract, thickish or 

 somewhat thin, whitish or greyish-white (K + yellow, CaCl , 

 I ~ i UT. ) Apothecia in globulose, pulverulent verrucae ; epithe- 

 cium dark or sordid-glaucous, somewhat plane, suffused ; spores 2nae, 

 0,080-15 mm. long, 0,050-82 mm. thick. Cromb. Grevillea, xii. 

 p. 57 ; Leight. Lich. Fl. p. 238, et ed. 3, p. 228 pro parte. P. 

 syncarpa et /3. dealbata Mudd, Man. p. 273. Lichen dealbatus Ach. 

 Prodr. (1798) p. 29. Variolaria chlorothecia Tayl. in Mack. Fl. 

 Hib. ii. p. 114. Isidium paradoxum Turn. & Borr. Lich. Br. 

 p. 97 ; Sm. Eng. Fl. v. p. 231. Variolaria corallina Gray, Nat. 

 Arr. i. p. 492 ; Tayl. in Mack. Fl. Hib. ii. p. 113. Brit. Exs. : 

 Leight, 11. 320 ; Mudd, n. 261. 



