26 LECANO-LECIDEBI [lECIDBA 



simple, short, with straight spermatia 0,005-6 mm. long, scarcely 

 0,001 mm. thick. Several varieties and forms have been enumerated 

 by authors. 



Hah. On peaty ground, not unfrequently on stumps of dead firs, 

 rarely iucrusting mosses, from upland to alpine situations. — Distr. 

 General and common in Great Britain, no doubt also in Ireland, very 

 abundant on the Grampians ; not seen from the Channel Islands. — 

 B. M. Epping Forest, Essex ; Ightham, Kent ; New Forest, Hants ; 

 Dartmoor, Devon ; North Wootton Coromon, Norfolk ; near Buxton, 

 Derbyshire ; Liokey Hills, Worcestershire ; Oader Idris, Merioneth ; 

 Stiperstones Hill, Shropshire ; Guisboro' Moor and Ayton Moor, 

 Cleveland, Yorkshire ; Eglestone, Durham ; near Hexham, North- 

 umberland ; Pentland Hills, near Edinbmrgh ; Achosragan Hill, Appin, 

 Argyll ; Cockhill, Callander, Craig Calliach, Ben Lawers and Eannoch, 

 Perthshire ; Clova, Forfarshire ; Countesswells Wood, near Aberdeen ; 

 Glen Dee and Ben-naboord, Braemar, Aberdeenshire; Glen Nevis, 

 Invemessshire ; Lairg, Sutherland ; The Storr, Island of Skye ; Apple- 

 cross, Eossshire; near Belfast, Antrim; Doveraile Mts., Cork; 

 KiUamey, Kerry ; Delphi, Oonnemara, Galway. 



Form 1. saxatilis Larb. in Leight. Lich. Flora, ed. 3, p. 259 

 (1879) (nomen). — ^Thallus ysty thin, the granules scattered, 

 subevanescent. Apothecia subminute, livid-brown ; otherwise as 

 in the type. 



Exsicc. Larb. Lich. Hb. n. 101. 



Evidently only a depauperate state of the type, resulting from the 

 nature of the substratum on which it is erratic. In the specimen seen 

 the apothecia are either solitary or here and there confluent. 



Sab. On moist rocks in an upland district. — B. M. By Lough Muck, 

 Connemara, Galway (the only locality). 



Form 2. viridula Oromb. — Thallus granulose-leprose, greyish- 

 green, the granules at length deliquescent, pulverulent, yellowish. 

 Apothecia somewhat small, blackish, solitary or confluent ; 

 otherwise as in the type. — L. decolorans var. y viridula Mudd 

 Man. p. 197 (1861) ; form aporetica (vix Koerb. non Ach.) 

 Leight. Lich. Fl. ed. 3, p. 259 (1879). 



Exsiue. Mudd n. 166. 



Differs merely in the colour of the more leprose thallus, which is 

 dark-green when moist. It is apparently only one of the numerous 

 conditions of this polymorphous plant, affected by atmospheric 

 influences. 



3db. On peaty groimd in an upland tract. — B. M. Cliffrigg, Cleve- 

 land, Yorkshire (the only locality). 



Var. p escharoides Schser. Enum. p. 137 (1850). — Thallus 

 granulose-verrucose, greyish-white. Apothecia convex, subim- 

 marglnate, more or less confluent, brownish-black or black. — 

 L. decolorans var. j8 escharoides Mudd Man. p. 197 ; form 

 escharoides Leight. Lich. Fl. ed. 3, p. 258. Lichen escharoides 

 Ehrh. Crypt. Exs. n. 313 (1793). Lecidea decolorans var. 

 desertorum (Ach. 1) Cromb. in Grevillea xxii. p. 9 (1893). 



