124 LECAMO-LECIDEEI [bIATOKIKA 



Lecidea pulverea Borr. in Engl. Bot. Suppl. t. 2726 (1831) ; 

 Hook, in Sm. Engl. Fl. p. 181 ; Tayl. in Mackay Fl. Hib. ii. 

 p. 126 ; Cromb. Lich. Brit. p. 89 ; Leight. Lich. Fl. p. 322 ; ed. 

 3, p. 334. 



Exsicc. Bohl. n. 90; Cromb. n. 187; Larb. Lich. Hb. n. 150. 



Besembles B. lAghtfootii var. commutdta, bnt is easily dis- 

 tingnished by the laiger spores. The apothecia are, according to 

 Hylander (Flora 11. p. 347), at times pale-flesh-colonred, which is not 

 the case in the British specimens. 



Sab. On trunks of old trees generally near the roots, rarely 

 incmsting mosses on rocks in maritime and mountainous districts. — 

 Distr. Somewhat local, though usually plentiful where it occurs 

 throughout the British Isles. — B. M. Withiel, Cornwall ; near Torquay 

 and Lustleigh, Devon ; New Forest, Hants ; Ardingly and St. 

 Leonard's Forest, Sussex ; Capel Cym and Barmouth, Merioneth ; 

 Maltby Wood, Yorkshire ; Windermere, Westmoreland ; Keswick, 

 Cumberland ; Falls of Clyde, Lanark ; Barealdine, Argyll ; Glen 

 FaUoch, Glen Lochay and Aberfeldy, Perthshire ; GlengarifF, Cork ; 

 Mangerton, lluckruss, Dromore and Turk Mt., Kerry ; Addergoole, 

 near Kvlemore, Glendalough and Doughruagh Mt., Galway. 



25. B. Lightfootii Mudd :Man. p. 179 (1861).— Thallus 

 determinate or subeffuse, thickish, granulose-verrncose, greenish- 

 white or greenish-grey (K— , CaCl — ). Apothecia moderate, 

 subinnate-sessile, plane or rather convex, slightly shining, dark- 

 brown or black, margined, the margin thin, smooth, entire or 

 flexuose, paler ; paraphyses concrete, brown at the apices ; hypo- 

 thecium pale-greyish ; spores ellipsoid, faintly 1 -septate, constricted 

 in the middle. — Lichen Lightfootii Sm. Engl. Bot. 1. 1451 (1805). 

 Lecidea Lightfootii Ach. Lich. Univ. p. 177 (1810) ; S. F. Gray 

 Nat. Arr. i. p. 469; Hook, in Sm. Engl. Fl. v. p. 180 ; Cromb. 

 Lich. Brit. p. 65 ; Leight. Lich. Fl. p. 319 ; ed. 3, p. 333. 



Exsicc. Larb. Lich. Hb. n. 106. 



Somewhat similar in habit and appearance to L. parasema. The 

 innate apothecia occasionally seem as it crowned by the thalline 

 granules, which, in conjunction with their paler margin, suggests a 

 Lecanora ; there are, however, no traces of a true thalline mai^in. 

 In some habitats (e.g. firs) the thallus is much thinner ^\-ith the 

 granules more scattered and the apothecia smaller. The spermogones 

 are small and brown ; the spermatia subglobose and very minute 

 0,002 mm. long, 0,0015 mm. thick. 



Hub. On the smooth trunks of trees, chiefly birch, rarely fir, in 

 upland wooded districts. — Distr. Not unfrequent in England, AVales, 

 and S. Ireland. — B. M. Eeigate HjU, Surrey ; St. Leomird's Forest, 

 Ardingly Kocks, near Parham, near Petworth, near Eastham, 

 Cuckfield, Hayward's Heath and Wiggonbolt Common, Sussex ; 

 Lyndhurst, New Forest, Hants ; UUacombe, Dartmoor, Devon ; 

 Lewknor, Oxfordshire ; near Baider Du, Eadnorshire ; Dolymelynen 

 and Nannau, DolgeUy, Merioneth ; Baysdale, Cleveland, Yorkshire ; 

 Biverstown, Cork ; Dunkerron, Kerry. 



"Var. yS commutata Mudd /. c. — Thallus granulose-leprose or 

 STibpulverulent, greenish-grey. Apothecia as in the type. — Leca- 



