418 LICHENACEI. [LECAXORA. 



S.W. Highlands of Scotland and N.W. Ireland. B. M. : Glen Creran, 

 Barcaldine, Argyleshire. Letterfrack, Connemara, co. Galway. 



97. L. prajpostera Nyl. Flora, 1873, p. 19. Thallus deter- 

 minate, thin, smoothish, areolato-rimose, whitish, darkly limited and 

 subfimbriate at the circumference (K + yellow, then cinnabarine- 

 reddish, CaCl ). Apothecia moderate, blackish, opaque, glaucous- 

 suffused or subdenudate, the thalline margin rugulose or subcrenate ; 

 spores ellipsoid, 0,009-14 mm. long, 0,005-6 mm. thick ; paraphyses 

 slender ; epithecium yellow-inspersed ; hymenial gelatine, especially 

 the thecae, bluish with iodine. Cromb. Grevillea, 1873, p. 141 ; 

 Leight. Lich. Fl. ed. 3, p. 173. 



Looks at first sight as if only a peculiar variety of L. atrynea, but is 

 well distinguished by the smaller spores, the reactions of the thallus and 

 hymenial gelatine. The two specimens seen by me are evidently an old 

 state of the plant, and though the apothecia are numerous the spores are 

 seldom present, 



Hob. On basaltic rocks in a maritime district Distr. Extremely 

 local and rare in one of the Channel Islands. B. M. : Rozel, Island of 

 Jersey. 



98. L. albella Ach. Vet. Ak. Handl. 1810, p. 137 ; Nyl. Flora, 

 1872, p. 365. Thallus determinate, thin, smooth, whitish (K + 

 yellow, CaCl ). Apothecia moderate, plane or slightly convex, pale- 

 flesh-coloured, caesio-pruinose or naked, the thalline margin entire ; 

 paraphyses not very discrete ; epithecium granulose (CaCl ) ; spores 

 0,010-12 mm. long, 0,005-8 mm. thick ; hymenial gelatine bluish, 

 then nearly colourless or somewhat yellowish, the thecse tawny 

 wine-red (their apices bluish) with iodine. Gray, Nat. Arr. i. 

 p. 453-; Sru. Eng. Fl. v. p. 191 ; Mudd, Man. p. 148 ; Cromb. Lich. 

 Brit. p. 51 ; Leight. Lich. Fl. ed. 3, p. 206. L. subfusca forma 

 albella Leight. Lich. Fl. ed. i. p. 204. Lichen albellus Pers. in list. 

 Ann. Bot. xi. (1794) p. 18 ; Eng. Bot. t. 2154. 



In several respects allied to more than one of the preceding species, from 

 which externally it may be discriminated by the pale buff-coloured apo- 

 thecia, which are rather scattered or sometimes crowded. It is, however, 

 more definitely separated by the spermogones, which, as stated by Nylander 

 (Flora, 1872, p. 250, note 2), are pale above. The spermatia are 

 0,016-20 mm. long ( f de Nyl. in Hit.). It is a somewhat variable plant, 

 presenting the following forms. 



Hab. On smooth bark of trees in wooded maritime and upland districts. 

 Distr, As yet only here and there sparingly in Great Britain and Ire- 

 land. B. M. : Epping Forest, Essex ; New Forest, Hants ; Falls of 

 Becky, S. Devon ; Savemake Forest, Wiltshire ; Hay Park, Hereford- 

 shire ; Island of Anglesea. Barcaldine, Argyleshire ; Morrone, Braemar, 

 Aberdeenshire. Killaloe, co. Clare. 



Form 1. peralbella Nyl. ex Cromb. Journ. Bot. 1876, p. 361. 

 Thallus as in the type. Apothecia small, pale-brownish, slightly 

 pruinose ; hymenial gelatine bluish, then wine-red with iodine. 



