Rev. W. A. Leigh ton on the Lichens of Cader Idris. 403 



but a few specimens of Endocarpon ftuviatiley DC. The sun now 

 broke through the clouds, and tempted me to ascend to the 

 Llyns Gafr and Gader, collecting on the way Lecidea lithophila, 

 Ach., L. fusco-atra, Ach., L. contigua, Fr., in various states and 

 stages, one with curious subgyrose apothecia arising from the 

 inserted growth of an Alga, and another in which the apothecia 

 were broken up into several clustered smaller apothecia; L. la- 

 picida, Fr., and its var. declinans, Nyl. (new to Great Britain), 

 L. umbrina, Ach., and its form vermifera, Nyl., L. petrcea, Flot., 

 in various states, L. lutosa, Mont., thallo denudato, L. atro- 

 alba, Flot., Endococcus erraticus (Mass.) and gemmifer (Tayl.), 

 the latter in an unusual state, sine thallo substrato ; Lecanora 

 cinerea (L.) and calcarea, Ach., L. badia, Ach., and its var. 

 cinerascens, Nyl. (new to Great Britain), L. atra, Ach., and L. 

 leucophaa, Flk. (new to Great Britain), Stereocaulon Cereolus, 

 Borr., and S. denudaturrij Flk., and the following entirely new 

 species : — 



Lecidea subnigrata, Nyl. 



Thus characterized by Dr. Nylander in the 'Flora,' 1866, p. 370 : 



" Thallus obscure cinerascens, granulosus, diffractus ; apothecia 

 fusco-nigra vel spadiceo-nigricantia vel rufo-nigra, convexa, 

 immarginata, saspius conglomerata, intus concoloria ; sporae 

 8, incolores, ellipsoideae, l-septatse, long.0'009-0'011 millim., 

 crass. 0-004-0'005 millim. ; epithecium sordide lutescens; 

 paraphyses non discretse; hypothecium incolor. - Gelatina 

 hymenea iodo caerulescens. Vix separanda a L. denigrata" 



Lecidea biformigeray Leight. 



Thallus sordide albus, tartareus, crassus, verrucoso-areolatus, 

 rimoso-diffractus ; apothecia conglomerata, nigra, parva, plana, 

 tenuiter marginata; hypothecium pallidum; sporae 8, inco- 

 lores, anguste oblongse, l-septatse, loculis binucleolatis. 



Spores very similar in shape and size to those of Verrucaria 

 biformis, Borr. 



Also, in very small quantity (and new to Britain), Lecidea 

 Dufoureiy Ach. herb., which Dr. Nylander considers to be a good 

 species, but which he has forgotten to insert in his * Lich. Gall.' 

 although the lichen has been known to him for fifteen years 

 past. 



Arrived at the lakes, the promising sunshine and the appa- 

 rently short distance to the summit tempted me to persevere 

 and endeavour to reach it, purposing to return eastwards over 

 the ridge to Dolgelley. Noticing a well-marked road at a con- 



