388 LICHENACEI. [lECAXORA. 



Hah. On calcareous rocks, rareh' on flints in maritime and mountainous 

 districts. — Distr. Rather local, though common where it occurs in Great 

 Britain ; not seen from Ireland. — B. M. : Reigate, Surrey ; Lydd Beach, 

 Kent; Peasemarsh and near Lewes, Sussex; Isle of Wioht; Cunning 

 Dale, Buxton, Derbyshire ; Island of Anglesea ; C"raig-y-Rhiw, Oswestry, 

 Shropshire ; JEglestone, Durham ; Ley en's Park, Westmoreland ; By well, 

 Northumberland. Kings Park, Edinburgh; Achrosagan HiU, Appin, 

 and near Ben Cruachan, Argyleshire ; Craig Tulloeh, Blair Athole, Perth- 

 shire ; Craig Guie and Morrone, Braemar, Aberdeenshu-e. 



Form incrustans Cromb. Greyillea, xyiii. (1889) p. 46. — Thallus 

 yery thiu, white, usually eyauescent. Apothecia minute, immersed, 

 plane or slightly conyex, thinly margined. — Lecanora rupestris 

 forma incrustans Leight. Lich. Fl. p. 191, ed. 3, p. 203. Lecidea 

 rupestris /3. incrustans Mudd, Man. p. 194. Patellaria incrustans 

 DC. Fl. Fr. ii. (1805) p. 361. 



DifFere in the smaller, immersed, margined apothecia, which, if a con- 

 stant character, would render it a distinct yarietv. At times, howeyer, 

 these in the same specimen become at length somewhat prominent and 

 immarginate, so that it can rank only as a form. 



Hab. On calcareous rocks in maritime and mountainous districts. — 

 Bisfr. Seen only from S.W. England, the S.W. Highlands, and the N. 

 Grampians, Scotland, though reported also by Leighton from W. England 

 (Ludlow, Shropshire). — B. M. : Anstey's Coye, Torquay, S. Deyon. 

 Island of Lismore, Argyleshire ; Morrone, Braemar, Aberdeenshire. 



Subsp. L. Siebenhaariana Xyl. ex Stiz. St. GaU. Xat. Ges. 1874, 

 p. 215. — Thallus effuse, rimoso-areolate, unequal, whitish or greyish. 

 Apothecia small, adnate, conyex, at first orange-coloured, at length 

 sordid-oliye or brownish tawny-yellow, internally dark ; spores as 

 in the type. — Cromb. Journ. Bot, 1885, p. 195. — Biatora Sleben- 

 haariana Koerb. Syst. Lich. Germ. (1855) p. 207. 



Characterized by the diflerently coloured apothecia and the dark hypo- 

 thecium. This, as observed by Fries fil., Lich. Scand. p. 42o, in the 

 young apothecia is usually yiolet-rose-coloured, then becomiug more and 

 more brownish, though in these it at times presents the natural colour of 

 the type. The thallus is at times almost eyanescent and visible only 

 arouiid the apothecia, which are small and scattered, or minute and 

 seyeral congregate. 



Hab. On moist mica-schist rocks in alpine situations. — Distr. Very 

 sparingly on two of the S. Grampians, Scotland. — B. M. : Summits of 

 Ben Lawers and Craig CaUiach, Perthshire. 



50. L. nivalis Xyl. Xot. Sallsk. pro F. & Fl. F. Forh. v. (1866) 

 p. 129. — ThaUus effuse, very thin or slightly granulate, whitish or 

 greyish-white (K-j- purplish). Apothecia small, adnate, ochraceous 

 or orange-coloured, at first plane with an evanescent thalline mar- 

 gin, at length somewhat convex, biatorine with thin, entire proper 

 margin (K -1- purplish) ; spores oblongo-eylindrical, simple or faintly 

 1-scptate, 0,024-38 mm. long, 0,005-7 mm. thick; paraphysea 



