1ECANORA.] LECANO-LECIDEEI. 437 



124. L. metaboloides Nyl. Flora, 1872, p. 250. Thallus effuse, 

 subgranulose, thin, whitish, often evanescent (K + yellow, CaCl ). 

 Apothecia small, biatoroid, at first plane and thinly margined, then 

 convex, immarginate, pale, livid-brown or blackish, naked or 

 slightly prninose; spores oblongo-ellipsoid, 0,007-11 mm. long, 

 0,0035 mm. thick ; hymenial gelatine persistently bluish with 

 iodine. Cromb. Journ. Bot. 1882, p. 274. To this, fide Nyl. 

 Flora, 1881, p. 184, is referable Biatora sarcopisioides Mass. Rich. 

 Lich. (1852) p. 128 ; Lecidea minuta var. sarcopisioides Cromb. 

 Lich. Brit. p. 69 ; Leight. Lich. PL p. 266, ed. 3, p. 264. This, 

 however, is a mere state of Nylander's plant, whose name has a 

 wider and more definite signification. Brit. Exs. : Cromb. n. 162 

 pro parte. 



Looks quite a Biatora, but the spermogones show its true relation. 

 It is a somewhat variable plant both as to thallus and apothecia, though 

 the differences in these merely indicate states resulting from habitat. The 

 thallus is seldom well developed, and usually is entirely obsolete. At 

 times it is dark-greyish with blackish apothecia (form obscurior Cromb. 

 Grovillea, xviii. p. 69). It spreads very extensively over the substratum, 

 and is always abundantly fertile. 



Hab. On old pales, decorticated stumps of trees, rarely on stems of 

 gorse, in maritime and upland wooded tracts. Distr. Sparingly in S.W. 

 and N. England ; abundant among the S. and Central Grampians, Scot- 

 land. B. M. : Shanklin, Isle of Wight ; New Forest, Hampshire; 

 Stiperstones, Shropshire; Cleveland, Yorkshire; Ennerdale, Cumber- 

 land. Achmore, Glen Lochay arid Fiularig, Killin ; Glen Fender, Blair 

 Athole, Perthshire. 



125. L. polytropa Schaer, Enum. (1850) p. 81 pro parte; Nyl. 

 Flora, 1872, p. 251. Thallus subdeterminate or effuse, granu- 

 late- or rimoso-areolate, or subsquamulose, pale sulphur-coloured 

 or yellowish-green, often subevanescent (K + yellowish, CaCl ); 

 hypothallus, when present, thin, black. Apothecia small or 

 moderate, adnate, usually biatorine, at first plane with thin, 

 entire, subflexuose margin, at length convex, with the margin 

 excluded, yellowish-flesb-coloured or pale-testaceous ; spores ellip- 

 soid, 0,010-13 mm. long, 0,005-6 mm. thick ; paraphyses slender 

 or not well discrete ; hymenial gelatine bluish, then sordid- 

 violet with iodine. Cromb. Grevillea, xviii. p. 69 ; Mudd, Man. 

 p. 151 ; Leight. Lich. PL p. 197, ed. 3, p. 180. Lecanora varia 

 var. polytropa Cromb. Lich. Brit. p. 52. Lecidea polytropa Gray, 

 Nat. Arr. i. p. 475 ; Sm. Eng. PL v. p. 185. Lecidea Ehrhartiana 

 ft. polytropa Hook. Fl. Scot. ii. p. 40. Lichen polytropus Ehrh. 

 Crypt, (1793) n. 294; Dicks. Crypt, fasc. iv. p. 22; Eng. Bot. 

 t. 1264 (two lower figs.). .Sri*. Exs. : Leight. n. 179 (atypical). 



Often regarded as only a saxicolous variety of L. varia, this has now 

 been definitely separated by Nylander on account of the different cha- 

 racters it present*. At the same time it is a very variable species both as 

 to the thallus and apothecia. The thallus, which frequently spreads 

 extensively, varies in thickness and at times is scarcely, if at all, visible, 

 whence var. acrusfacea Schaer, Mudd, Man. p. 151 ; Leight. Exs. cit. A 



