320 LICHEKACEI. [l>HYSCIA. 



Var. ft. virella Cromb. Grevillea, xv. p. 78. Thallus subeffuse, 

 pale greyish -green, here and there greenish- or yellowish-sorediate ; 

 lacinise short, imbricate, with horizontal cilia at the margins. Apo- 

 thecia small or submoderate, the receptacle blaek-fibrillose at the 

 base. Ptiyscia obscura var. virella Leight. Lich. Fl. p. 148, ed. 3, 

 p. 137. Borrera obscura y. virella Mudd, Man. p. 110. Parrnelia 

 virella Sm. Eng. Fl. Y. p. 202. Lichen virellus Ach. Prodr. (1798) 

 p. 108 ; Eng. Bot. fc. 1696 (two upper figs.). Lichenoides viride, 

 seqmentis angustis distortis. scutellis 2Jullis Dill. Muse. 178, t. 24. 

 f. 72 v.Brit. Exs. : Mudd, n. 80 ; Larb. Lich. Hb. n. 126. 



Overlooking the character of the marginal cilia of the lacinise and of 

 the receptacle of the apothecia, licheuologists have associated this distinct 

 variety with P. obscura. As suggested by Nylander in lift., and confirmed 

 by a specimen from Acharius in Herb. Linn. Soc. (fragmentary and 

 abraded, though sufficient for recognition), it entirely belongs to this 

 species. It differs from the type in the thallus being more effuse, often 

 less closely appressed, paler in colour, and sprinkled with, or at. times 

 almost covered by, roundish soredia, as also in the shorter and usually 

 more imbricate laciniae. When wet it is of a bright-green colour, and 

 when growing associated with P. parietina it is suffused with chryso- 

 phanic acid, when the thallus and soredia are more or less yellowish (form 

 -flavescens Cromb.). It then gives a purplish reaction with K, which, 

 however, is quite abnormal. To this state is referable Physcia endococ- 

 cina (non Koerb.) Cromb. Joum. Bot. 1872, p. 359; Leight. Lich. Fl. 

 ed. 3, p. 142. The cilia of the laciniee and the apothecia (frequently 

 absent in the latter, as they occasionally are in the type itself) are at first 

 pale, speedily becoming brownish, and at length in old plants blackish. 

 The apothecia and the spermogones are frequent in our specimens. 



Hob. On the trunks of old trees, rarely on walls, in maritime and up- 

 land districts. Distr. Not uncommon in most parts of England ; appa- 

 rently rare in N. Wales, Scotland, and S.E. Ireland. B. M. : Kennetand 

 Ickworth, Suffolk ; Epping Forest, Essex ; Heniield and near Brighton, 

 Sussex; Hyde, Isle of Wight; Ilsham, Torquay, Devonshire; Newlyn 

 Cliff, Penzance, Cornwall ; near Cirencester and Honeybourne, Glouces- 

 tershire ; Gogmagog Hills, Cambridgeshire ; Darley, Derbyshire ; Aber- 

 dovey, Merionethshire ; Ayton, Cleveland, Yorkshire ; near Hexham, 

 Northumberland. Airds, Appin, Argyleshire ; Finlarig, Killin, ai:d Glen 

 Fender, Blair Athole, Perthshire. Killaloe, co. Cork; Lyons, near 

 Dublin. 



1. Spermogones with long acicular spermatia. 



24. P. adglutinata Nyl. Flora, 1862, p. 355. Thallus small, 

 orbicular, closely agglutinate, imbricato-stellate, sordid greenish- 

 grey ; beneath blackish, scarcely fibrillose at the margins ; lacinias 

 very narrow, multifid at the circumference, subleprose in the centre 

 (K~~, CaCl~). Apothecia small, plane, brownish-black, thethalline 

 margin entire ; spores ellipsoid, 0,014-21 mm. long, 0,008-10 mm. 

 thick. Cromb. Lich. Brit. p. 40 ; Leight. Lich. Fl. ed. 3, p. 137. 

 Borrera obscura e. adglutinata Mudd, Man. p. 110 ; Leight. Lich. Fl. 

 p. 149. Lecanora adglutinata Florke Deutsch. Lich. iv. (1815) p. 7 ; 

 Tayl. in Mack. Fl. Hib. ii. p. 146. Parmelia elaina Gray, Nat. Arr. 



