386 LICHEXACEI. [lECANOEA. 



Often confounded with or regarded only as a variety of L. pi/racea, to 

 ■uhich it is externally similar, though definitely separated by the dis- 

 tinctly-septate spores. It spreads extensively over the substratum, the 

 thalliis being frequently evanescent. The apothecia are very numerou.s, 

 and at times much crou'ded with a thalline margin rarely visible in their 

 earlier stao-e of growth. Though uorniAlly a corticolous plant, it at 

 times occurs on chalk, mortar, and limestone (very rarely in Britain), 

 when it is form rupest)-is {? Scop.) Xyl. Lich. Scand. p. 145 : Lecidea 

 ttlmicola Tayl. in Mack. Fl. Hib. ii. p. 129. 



Hah. On the trunks of trees, chiefly elms, rarely on rocks, from mari- 

 time to upland situations. — Distr. General in most parts of England, 

 apparently rare in N. Wales, Scotland, and S. Ireland. — B. M. : Great 

 Glenham and near Sotterly, Suffolk; Hale End, Eppiug Forest, Essex; 

 Evnsford, Kent ; Lewes and Glynde, Sussex ; near Ventnor, Isle of 

 Wicrht ; near Cirencester, Gloucestershire ; near Mill Hill, Middlesex ; 

 Elstree, Herts ; Windsor Great Park, Berkshire ; Stowe Park, Bucking- 

 ham ; Wirapole Park, Cambridgeshire ; Twycross, Leicestershire ; near 

 Worcester and at North Malvern, Worcestershire ; Island of Anglesea ; 

 near Masham, Yorkshire; Leven's Bridge, Westmoreland ; MeldonPark, 

 Wansbeck Vallev, Northumberland. Doune Castle, near Stirling ; 

 Pitfour, Aberdeeiisliire. Cattle Connell, co. Limeiick ; Rostellan, co. 

 Cork ; Inisfallen, Killaruey, co. Kerry. The saxicolous state has occurred 

 onlv in the following localities in S. audN. England and S.W. Ireland : — 

 South Downs, Sussex ; Newton Abbot, S. Devon ; Ingleborough, York- 

 shire. Dunkerron, co. Kerry. 



48. L. pUogina Nyl. Mem, Sec. Clierh. v. (1857) p. 112; Lich. 

 Scand. p. 141. — Tliallus effuse, very thin, minutely granuloso- 

 leprose, citrine or yellowish-green ; granules globular, often some- 

 what scattered (K-|-j)iirplish). Apothecia small, biatorine, plane or 

 at length convex, yellowish-orange : spores cUiptico-oblong, polari- 

 bilocular, 0,011-15 mm. long, 0,006-9 mm. thick. — Cromb. Journ. 

 Bot. 1871, p. 178; Leight, Lich. Fl. p. 223, ed. 3, p. 213.— Par- 

 melia citrina \?Lr. phJogina Ach. Meth. (1803) p. 180. — Brit. Exs. : 

 Larb. Lich. Hb. n. 57. 



Sometimes viewed as merely a corticolous state of L. cifrinn, but allied 

 rather to L. pi/racea, from which it is at once distinguished by the very 

 different thallus. The apothecia are generally rather scattered. 



Hab. On the trunks of old trees, ash and elm, rarely on old posts from 

 maritime to upland districts. — Distr. Found only in a few localities in 

 the Channel Islands and England. — B. M. : St. Clement's Bay, Island of 

 Jersey. Near Ilyde, Isle of Wight ; near Hastings, Sussex ; Penzance, 

 Cornwall ; Windsor Great Park, Berks ; Pampisford, Cambridgeshire ; 

 near Worcester ; Alston, Cumberland. 



Yar. /3. lutea Nyl. Lich. Scand. (1861) p. 142.— Thallus leproso- 

 pulverulent, whitish-citrine or pale-luteous. Apothecia pale-orange : 

 spores 0,011-12 mm. long, 0,006-7 mm. thick. — Cromb. Grevillea, 

 xviii. p. 46. — Lecidea epixantha var. lutea Ach. Lich. Univ. (1810) 

 p. 20'J. 



A peculiar variety, differing in the more pulverulent, paler thallus, the 

 paler apothecia, smaller spores, and the nature of the habitat. The few 

 British specimens are well fertile. 



