500 XICHEXACEI. [PERTCSAEIA. 



Barcaldine, Argvleshire ; Glen Lochay, S. of Loch Tay, Ivillin and 

 Balthayock Wood.*, near Perth, Perthshire : Countesswells "Woods near 

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

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

 CO. Cork ; Dunkerron, co. Kerry. 



Porm rupestris DC. Fl. Fr. ii. (1805) p. 320 ; Xyl. Flora, 1881, 

 p, 456. — pertile verrucse more or less aggregato-difform, verrucoso- 

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

 syn.) ; Leight. Lich. Fl. p. 239, ed. 3, p. 230. — Pertusaria rupestris 

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

 merely a darker state. — Brit. Exs. : Mudd, n. 259. 



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

 except in the thallus being usually more verrucose. 



Hab. On rocks in maritime and upland districts. — Distr. Only 

 sparingly in S. and N. England and the S.AV. Highlands of Scotland. — 

 B. M. : 'Hastings. Sussex : Ayton, Cleveland, Yorkshire ; near \\'hite- 

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

 Perthshii-e. 



Subsp. P, areolata Xyl. ex Hue, Eev. Bot. 1886, p. 74. — 

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



densely papillate, grepsh -white (K '\_ yellow). Apothecia as in 



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

 Grevillea, xix. p. 59. Tlielotrema 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.\\^. Highlands 

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

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

 Ilos.s-shire. 



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

 syn, P. lactescens) ; Flora, 1880, p. 39(>.— Thallus subiudetermi- 

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

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

 I ~ 1 bl ^* 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. 8, p. 228 pro parte.— P. 

 sjincarpa et /3. deaJhata Mudd, Man. p. 273. Lichen dealhatus Ach. 

 Prodr. (1798) p. 29. VarioJaria cMorothecia Tayl. in Mack. Fl. 

 Hib. ii. p. 114. Tsidium paradoxum Tiun. & 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. IVd.—Brii. Exs. : 

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



