400 ricHENACEi. [lecanora. 



marginate, brownish-black ; spores broadly ellipsoid, very obtuse at 

 the apices, with a broad transverse septum, 0,016-20 mm. long, 

 0,008-12 mm. thick; paraphyses not very discrete, brownish at the 

 clavate apices : hymenial gelatine bluish, the thecae violet -coloured, 

 with iodine. — Cromb. Journ. Bot. 1875, p. 141 ; Leight. Lich. Fl. 

 ed. 3, p. 220. — Psora Bischoffii Hepp, Lich. Europ. (1853) n. 81. 



WeU distinguished from the allied species by the broad septum of the 

 spores. In our few British specimens the thallus is little visible, but the 

 apothecia are numerous. When these are immarginate the plant has 

 entirely a lecideine appearance. 



Ilab. Ou calcareous rocks in upland situations. — Disfr. As yet only in 

 W. England and the Central Grampians, Scotland ; no doubt overlooked 

 elsewhere. — B. M. : Rodmarton and Stroud Road, Gloucestershire ; En- 

 uerdale, Cumberland. Craig TuUoch, Blair Athole, Perthshire. 



Yar. /3. immersa Cromb. Journ. Bot. 1876, p. 360. — Thallus 

 evanescent. Apothecia foveolato - immersed, somewhat plane, 

 blackish, the margin brownish, involute. — Leight. Lich. Fl. ed. 3, 

 p. 221. — Rinodina Bischoffii /3. immersa Koerb. Par. Lich. (1865) 

 p. 75. 



A rather inconspicuous plant, diflFering from the type in the immersed 

 apothecia, with their usually involute margin. The thallus is generally 

 confused with the stone, but when visible it is whitish and maciilar. 



Hab. On calcareous rocks and walls in hilly tracts. — Distr. Local 

 and scarce in S.W. England. — B. M. : Yatton and "Weston-super-Alai-e, 

 Somersetshire. 



70. L. colobina Ach. Lich. Univ. (1810) p. 358. — Thallus sub- 

 determinate, thinnish, granulato - pulverulent, ctesio - greyish or 

 grevish-black (K + purplish). Apothecia minute, adnate, somewhat 

 plane, blackish ; the thalline margin entire, thickish, cassio-greyish ; 

 spores oblongo-ellipsoid, sometimes slightly constricted in the middle, 



.0,016-20 mm. long, 0,007-9 mm. thick ; epithecium K-|-purplish. — 

 Cromb. Journ. Bot. 1882, p. 2Td.—BriL Exs. : Larb. Lich. Hb. 

 n. 91. 



A o-ood species, readily distinguished from its immediate allies by the 

 different reactions. In \he single British specimen seen the thallus is 

 leprose, dark, aud the apothecia only sparingly present. 



Hab. On the trunks of old elms in a lowland district. — I)ist>: As yet 

 onlv verv sparingly in E. England ; no doubt to be detected elsewhere. 

 — B. M.': Near Cambridge. 



71. L. Conradi Xyl. Xot. Sallsk, pro F. et Fl. Fenn. Forh. 

 xi. (1^71) P- 182. — Thallus subeffuse, verrucoso- or subleproso- 

 granulate, thinnish, griseous or greyish -brown (K — , CaCl-). 

 Apothecia moderate, plane, blackish-brown, opaque, with the 

 thalline margin rugulose or obsoletely crcnulate, at length convex 

 and immarginate; spores 4-locular, the cells nucleolate, 0,u26-32 



