lecideaJ lecideace^ 67 



113. L. contigua Fr. Lich. Eur. p. 298 (1831) pro parte. — 

 Thallus greyish-white or sometimes ashy -grey, usually rather 

 thin, continuous, finely cracked granular or areolate, the areolae 

 continuous and flat or sometimes convex and somewhat tumid (K — , 

 CaCl — ); hypothallus black. Apothecia seated on the thallus, 

 varying in size, plane or convex, somewhat rough, the margin 

 thick, obtuse, prominent, or sometimes almost obliterated ; hypo- 

 thecium thick, blackish-brown ; paraphyses slender, subcoherent, 

 dark- or olivaceous-brown at the apices ; spores ellipsoid, large, 

 0,016-27 mm. long, 0,008-13 mm. thick ; hymenial gelatine blue 

 then wine-red with iodine. — Mudd Man. p. 209 (excl. syn. ; spore 

 measurements too small) ; Cromb. Lich. Brit. p. 80 (excl. vars. 

 crustulata and speirea) ; Leight. Lich. Fl. p. 292 ; ed. 3, p. 299 

 (excl. forms meiospora and aygerata). Verrucaria contigua HofFm. 

 Deutschl. Fl. ii. p. 184 (1795). 



The thallus and apothecia of this lichen vary considerably in 

 appearance, giving rise to a large number of varieties which have been 

 described by Leighton as forms. They are all distinguished by the 

 characters of the apothecium, its thick dark-coloured hypothecium 

 and somewhat large ellipsoid spores. When the thallus is limited 

 and intersected by the hypothallus, it is f. limitata Leight. (Lich. Fl. 

 p. 292 ; ed. 8, p. 299) ; when it occurs in round somewhat furfuraceous 

 patches v/ith rather small apothecia, it is f. leprosa Leight. (Z. c. 

 p. 293). Another series of forms have a thick well-developed thallus 

 and occasionally very large apothecia; var. nohilis Fr. {I. c. p. 301, 

 f, nohilis Leight. I. c. p. 293) is characterized by having the thallus 

 thick, tartareous, areolate and turgid ; while f. Hoffmanni Leight. 

 {I. c.) is lighter in colour and less turgid with larger apothecia. 

 In var, notahiUs Nyl. (in Not. Sallsk. Faun. & Fl. Fenn n. ser. i. 

 p. 241 (1859)), (f. notahilis Leight. I. c. ed. 3, p. 302), the thallus is 

 whitish and unequally minutely granulose, the granules dispersed or 

 sometimes in small clusters (acervulate) , resembling the thallus of 

 Stereocaulon cofidensatum. Leighton describes a further evidently 

 rare form as f. pustulata (Z. c. p. 302), which is yellowish-grey, 

 limited by the black hypothallus, and areolate, the areolae plane with 

 central sorediate protuberances ; some of these are enlarged into 

 orbicular, rather flat tubercles, in which are embedded a conglomera- 

 tion of minute marginate black apothecia. 



Hah. On rocks in maritime or hilly regions. — Distr. Common 

 throughout Great Britain and Ireland. — B. M. Endellion, Cornwall 

 (f. limitata) ; Crown, East Down, Dartmoor, Devon ; Leith Hill, 

 Surrey ; Charnwood Forest, Leicester ; near Malvern, Worcester ; 

 Caercaradoc, Haughiiiond Hill (f. leprosa), and near Ludlow, Shrop- 

 shire ; near Monmouth ; Aran Mawddwy, Llyn Aran, Cader Idris, 

 and Dolgelly, Merioneth ; Carnedd Dafydd, Nant Ffrancon and 

 Capel Curig, Carnarvon ; Roughton, Lincoln ; Ayton, Cleveland, 

 York>hire; Westwater, Forfar; Loch-na-gat, Ben Lawers, Killin, 

 Glen Lochay, Craig Calliach, and Ben-y-gloe, Perthshire ; Barcaldine, 

 Lome, Achosragan Hill, Appin and Island of Lismore, Argyll ; 

 Morrone, Braemar, Aberdeenshire. 



Form calcarea Leight. Lich. Fl. p. 292 (1871).— Thallus 

 creamy-white, tartareous, smooth, areolate, the areolae plane or 



p 2 



