432 LICHENACEI. [LECANORA. 



varia it at once differs in the leprose thallus, though in all other respects 

 it nearly agrees with that species (Nyl. in Hit.). The margin of the young 

 apothecia is leproso-pulverulent. 



Hab* On old beeches (near the roots) and on aged pines in wooded 

 upland tracts. Distr. Only a few localities in E., S., Central, and N. 

 England, but plentiful in these. B. M. : Near Highbeech, Epping Forest, 

 Essex; New Forest, Hampshire; near Buxton, Derbyshire; Overend, 

 Egremont, Cumberland. 



118. L. expallens Ach. Lich. Univ. (1810) p. 374. Thallus 

 effuse, thin or thinnish, leproso-pulveruleiit, pale-sulphur-coloured 

 (K + yellow, CaCl-1- orange-red). Apothecia small, lecanorine, sub- 

 innate, plane or slightly convex, pale-yellow or flesh-coloured, the 

 thalline margin thin, pulverulent, at length obliterated ; spores 

 ellipsoideo-oblong, 0,01116 mm. long, 0,004-5 mm. thick. 

 Cromb. Grevillea, xviii. p. 69 ; Leight. Lich. M. p. 199 pro parfe, 

 ed. 3, p. 184 pro parte. Lecidea expctllens Sm. Eng. Fl. v. p. 181 

 (excl. " on rocks ") ; Tayl. in Mack. Fl. Hib. ii. p. 127. Leprnria 

 expallens fers.JldeA.ch. 1. c. Lecanora varia ^. orosZAraMudd, Man. 

 p. 150. Lichen orostheus Eng. Bot. t. 1549. Brit. Ea-s. : Larb. 

 Lich. Hb. n. 216. 



Easily recognized by the colour of the leprose thallus, which spreads 

 very extensively over the substratum. In more shaded habitats it is 

 somewhat thicker, whitish-sulphureous, sterile, and might readily be 

 taken for a " Lepraria.'' The apothecia, which are comparatively rare, 

 are usually somewhat scattered, though at times several are subcon- 

 fluent. The sperm ogones, which, however, are much more frequent in 

 the following variety, have the spermatia 0,020 mm. long, 0,0009 mm. 

 thick (fide Nyl. in lift.). 



Hab. On the trunks of trees, firs and oaks, and on old pales in lowland 

 and upland districts. Distr. Here and there throughout England and in 

 N.Wales; rare in S.W. and N.W. Ireland; not seen from Scotland, 

 though no doubt it exists there in a leprarioid state. B. M. : Thetford, 

 Norfolk ; Ickworth, Suffolk ; Tetsworth, Oxfordshire ; New Forest, 

 Hants ; near Newton Abbot, Devonshire ; Coleshorne and Oakley Park, 

 Cirencester, Gloucestershire ; Upton, Worcestershire ; Dolgelly, Merio- 

 nethshire ; Garn Dingle, Denbighshire ; Island of Auglesea ; Airyholme 

 Wood and Bipon, Yorkshire ; St. Bees, Cumberland. Bally nahinch, 

 Connemara, co. Galway. 



Var. ft. lutescens Nyl. Flora, 1872, p. 248. Thallus minutely 

 granulato-pulverulent. Apothecia numerous, crowded, at length 

 convex, submoderate, sessile, with the thalline margin inflexed or 

 excluded. Cromb. Grevillea, xviii. p. 69. Lecanora lutescens 

 Cromb. Journ. Bot. 1873, p. 133 : Leight. Lich. Fl. ed. 3, p. 164. 

 Patellaria lutescens DC. Fl. Fr. ii. (1805) p. 354. Brit. Exs. : 

 Cromb. n. 65. 



Differs from the type, with which it has usually been confounded, in 

 the more granulose thallus, and the larger, sessile apothecia with epulve- 

 rulent thalline margin. These are often so numerous as almost to ob- 

 literate the thallus. 



