XECIDEa] LECIDEACEiE 23 



nearly as in the type. — L. coarctata form elacista Leight. Lich. 

 PI. p. 278 pro parte; ed. 3, p. 281 pro parte. Parmelia elacista 

 Ach. Meth. p. 159, t. iv. f . 4 (1803). Lecanora coarctata var. 8 

 elacista Mudd Man. p. 154 pro parte (1861). 



Exsicc. Mudd n. 124 ; Larb. Lich. Hb. nos. 41, 342; Johns, 

 n. 333. 



Differs in the thinner, often subpulverulent thallus and the smaller 

 apothecia, which are often blackish and immarginate in age. In both 

 respects, however, it presents diversities resulting chiefly from the 

 nature of the habitat. Thus when pulverulent the thallus is frequently 

 little visible, when it is form cotaria Cromb. in Grevillea xxii. p. 9 

 {Lecidea cotaria Ach. Meth. Suppl. p. 11 (1803)). Occasionally it is 

 entirely absent, when it is form dejjauperata Leight. Lich. Fl. ed. 8, 

 p. 282 (1879). The apothecia in a very young state are subglobose, with 

 the pseudo-thalline margin connivent, and concealing the epithecium ; 

 it is then form variolosa Leight. Lich. Fl. ed. 3, p. 282 (Flot. Lich. 

 Siles. p. 120), having, asAcharius says {I. c), the aspect of Verrucaria 

 leucocejpliala. Very rarely this margin is persistent and more or less 

 crenulate (form subcrenulata Croinb.). 



Hab. On rocks, walls, and stones in maritime and mountainous 

 districts. — Distr. Not uncommon in most parts of Great Britain and 

 probably also of Ireland ; not found with certainty in the Channel 

 Islands. — B. M. Leith Hill, Surrey ; Springfield near Chelmsford, and 

 Oalleywood Common, Essex ; St. Leonards and Fairlight Glen, near 

 Hastings, Sussex ; Luccomb and near Shanklin, Isle of Wight ; 

 Launceston, Withiel and Newlyn Cliff, Cornwall ; Axe Edge, Buxton, 

 Derbyshire ; Ledbury, Herefordshire ; Malvern, Worcestershire ; Dol- 

 gelly and Cader Idris, Merioneth ; near Ayton, Cleveland, Yorkshire ; 

 Egiestone, Durham ; Achosragan Hill, Appin, Argyll ; Ben Lawers 

 and Craig Tulloch, Perthshire ; near Portlethen, Kincardineshire ; 

 Craig Guie, Braemar, Aberdeenshire ; Bantry and Kilcully, Cork ; 

 Kylemore and Doughruagh Mt., Connemara, Galway. 



Var. y glebulosa Cromb. Lich. Brit. p. 76 (1870) & in 

 Grevillea xxii. p. 9. — Thallus determinate or subdeterminate, 

 thickish, verrucose-glebulose or subsquamulose, the squamules 

 tumid, somewhat scattered or crowded, minutely lobed at the 

 circumference, whitish or glaucous-white. Apothecia small, 

 plane or slightly convex, reddish-brown, becoming dark-red, the 

 margin thin, speedily evanescent ; otherwise as in the type.- — 

 L. coarctata f. glehulosa, f. involuta and f. ornata Leight. Lich. 

 FL p. 279 (1871); ed. 3, p. 281. Lichen glebulosus Sm. Engl. 

 Bot. t. 1955 (1809). Lepidoraa glebulosum S. F. Gray Nat. Arr. i. 

 p. 462 (1821). Lecanora coarctata var. /3 ornata Sommerf. 

 Suppl. Fl. Lapp. p. 92 (1826); Mudd Man. p. 154 pro parte. 

 L. coarctata var. /5 glebulosa Mudd and var. y involuta Mudd 

 Man. p. 154 (1861). L. involuta Tayl. in Mackay Fl. Hib. ii. p. 134 

 (1836). Psora glebulosa Hook, in Sm. Engl. Fl. v. p. 193 (1833). 



Exsicc. Leight. n. 149; Mudd, n. 123; Larb. Lich. Hb. 

 n. 170; Johns, n. 334. 



Perhaps a subspecies, looking when best developed as if it were 

 even a distinct species. It is then well marked, as stated by Sommer- 



