Eev. W. A. Leighton on the Lichens of Cader Idris. 199 



litliophila^ Acli., L. fuliginosa^ Tayl., L. concretely Wlilnb., 

 Cladoma cervicomis^ Ach., of immense size and in magnificent 

 fructification, Stereocmdon denudatum^ Flk., Placojpsis gelida^ 

 (L.), Lecanora atra (L.), L. leucojyhcea^ Flk., Lecanora hifor- 

 onigera, Leiglit., in beautiful condition, Bpilonema jiaradoxum^ 

 Born (sterile), and a curious composite Sjyhoiria growing pa- 

 rasitically on tlie tliallus of Parmelia saxatilis, L., having 

 spores 8, fuscous, fabasform or subelliptical, 3-septate. 



The following day (Tuesday) we ascended the pass to the 

 '' Giant's Pebbles," on which I collected Lecidea rusttcula, 

 NyL, L. fultginosa, Tayl., Lecanora leucojyhoia, Flk., and 

 Pilopho7-on Jibula, Tuck., new to Great Britain, and only before 

 known as occurring in the White Mountains, North America. 

 Thence over Geu Craig, where I gathered Lecidea cojitigua, 

 A.ch..^i.hydrophila. Descending on the north side to LlynAran, 

 we found Stereocaulon cereolinum^ a minor state of S. con- 

 densatum^ Hffm., Verrucaria irrigua, Tayl., Lecidea 'phcmpSy 

 Nyl. , and L.jurana, Schajr. Time pressing, we could not delay,, 

 but scrambled again to the summit, and descended by a very 

 formidable descent over projecting rocks and loose '' screes," 

 interspersed with safe grassy patches down the precipices 

 north of the lake into Llyn Cae, and so by the torrent-side 

 to MinfFord. This was rather a day of scrambling than of 

 collecting ; but we determined to devote Wednesday entirely to 

 Llyn Cae, where my gatherings were Lecidea contigua^ Ach., 

 f. oxydata (K — C — ), L. fuUginosa, Tayl., Ij.jurana^ Schter. 

 (K- C-), L. amphibia, Fr. (K-|- C + ), L. phcea, Ach.? 

 (K — C — ), Z. rivulosa, Ach. (K-f-), L. lapicida, Fr., var. de~ 

 clinans, Nyl. (K + ), L. petrcea, Flot., L. geographica, L., L. 

 j)hceops, Nyl. (K+ C + ), L. panceola, Ach. (K yellow, C red),, 

 L. consentiens, Nyl. (K— C — ) (new to Wales), Lecanora 

 cinerea (L.) (K + ), and its form. A char ii, E. Bot. 1087, L. 

 leucophcea, Flk., L. biformigera, Leight. (K+ C + ), Placopsis 

 gelida(L.) (K yellow, Cred), Opegrapha fesserato(r)C.)(K+ ), 

 Urceolaria scruposa, Ach., Lecayiora atra, Ach. (K + ), Endo- 

 coccus perpusiUus,l^j\., Verrucaria irr{gua,Tiij\., Pilophoron 

 Jibula, Tuck., in magnificent profusion, and a new species of 

 Lecidea, which I na,me plicatilis, and describe below. 



Thursday being the tether of our trip, we returned home- 

 wards. 



Lecidea panceola, Ach., is well represented in Fellm. Lich. 

 Lapp. Or. 182 ! Scliger. L. Helv. 469 ! and Anzi, Lich. Langob. 

 83 ! Its chemical reaction is K yellowish, C red. It is figured 

 under the name of athroocarpa in E. Bot. 1829. Mr. Borrer's 

 Herbarium at Kew contains it from Cader Idris, by Dickson 

 named " L. niveo-ater, Dicks.," also from " rocks above 



