LECANOKA.] LECAXO-LECinEEF. 40U 



Differs from the preceding species in the colour of the thallus and hypo- 

 thallus, in the character of the thalline margin, and in the simple spores. 

 The papillae of the thallus, which is either orbicular or somewhat ex- 

 panded, are minute, very much crowded, rather fragile, and form a some- 

 what thickish and superficially granulose crust. In moister situations it 

 is more greenish, its usual condition with us ; whence form spodopheea 

 Cromb. (Parmelia spodophaa Wahl. in Ach. Meth. Suppl. p. 37). The 

 apothecia are numerous and crowded, with the thalline margin persistent 

 and (except in very young apothecia) always creuulate. 



Hub. On granitic and schistose rocks in maritime districts. Distr. 

 Local, though usually plentiful in the Channel Islands, S.W. England, 

 and N.E. Scotland. B. M. : Le Fret, Island of Jersey. Tolpedn Pen- 

 with, and near Penzance, Cornwall. Portlethen, Kincardineshire. 



I. Thallus uniform, K+. 



86. L. subfusca Xyl. Flora, 1872, p. 250,nota 2. Thallus deter- 

 minate, thin, subsmooth, or slightly rugoso-uneqiial, whitish (K -J- 

 yellowish, CaCl ). Apothecia moderate, 

 plane or somewhat convex, brown or reddish- 

 brown, opaque or somewhat shining, the 

 thalline margin entire ; paraphyses slender, 

 discrete, brownish at the apices ; epithecium 

 non-granulose ; spores 0,01116 mm. long, 

 0,007-10 mm. thick ; hymenial gelatine 

 bluish, then dark-violet (the thecse dark 

 tawny-coloured) with iodine. Cromb. Gre- 

 villea, xviii. p. 68. L. subfusca form argen- 

 tata Cromb. Lich. Brit. p. 51 ; Leight. Lich. 

 Fl. p. 201, ed. 3, p. 186. L. subfusca y, 

 glabntta Mudd, Man. p. 146 pro parte. 

 L. subfusca Hook. Fl. Scot. ii. p. 47, Sm. 

 Eng. Fl. v. p. 189, is a nomen vagum pro 

 maxima parte (ut videtur). Brit. Exs. : 

 Larb. Lich. Herb. n. 217. 



Fig. 65. 



Lecanora subfusca Nyl. 

 a. A spore and para- 

 physis, X 350. b. Ste- 

 rigmata and spermatia, 

 X 500. 



A species until recently ill-defined and not well limited, several of 

 those which immediately follow being either confounded with it or 

 viewed simply as varieties. These are now separated chiefly by dif- 

 ferences in the paraphyses and epithecium, and also, according to 

 Nylander I. c., in the size of the spermatia. The typical state includes 

 Lecanora subfusca a. aryentata Ach. Lich. Univ. p. 893, and y. glabrata 

 Ach. 1. c., which do not differ from each other. The apothecia are usually 

 more or less crowded, rarely somewhat scattered. The spermogones have 

 the spermatia 0,016-19 mm. long (fde Nyl. inlitt.'), and in this, as in the 

 allied species, are black above. 



Hab. On trunks of trees, rarely on old pales, in maritime and lowland 

 tracts. Distr. Seen only from a" very few localities in E., S., and W. 

 England ; no doubt to be detected elsewhere. B. M. : Lyndhurst, New 

 Forest, Hants ; Ilsham, Torquay, S. Devon ; near Cambridge ; Churchill, 

 near Worcester. 



