306 PTKENOCABPEI [POLYBLASTIA 



Hab. On peaty earth between the squamules of Dermatocarpon. 

 cinereum. — B. M. Ben Lawers, Perthshire (the only British 

 locality). 



16. P. gothica Th. Fr. in Bot. Xot. 1865, p. 112.— ThaUus 

 thin, greenish or dark-coloured, effuse. Perithecia black, small, 

 semi-immersed, the ostiole indistinct ; perithecial wall entire ; 

 paraphyses indistinct ; ostiolar filaments short ; ascus rather 

 broad, subventricose ; spores ellipsoid, becoming somewhat fusi- 

 form, dark-brown, at first 3- then 5-7-.septate and irregularly 

 muriform, 0,018-28 mm. long, 0,007-9 mm. thick. — Verrucaria 

 ])iHpUoia Leight. Lich. Fl. p. 458 (1871) (fide Th. Fr. in. K. 

 Svensk. Yetensk. Soc. Nov. Act. 1877, 8, p. 26). V. gothica 

 Leight. torn. cit. ed. 3, p. 490 (1879). 



Th. Fries (?. c.) recognizes the resemblance of this species to a 

 SpJuei-ia . I have been unable to detect gonidia in Leighton's specimen , 

 but the size and strnctmre of the spores agree with Fries's description. 



Hab. On decaying mosses and humus (P. gothica) ; on larch-poles 

 {V. pituphloia). — Distr. Shrewsbury, Shropshire. 



17. P.? peltophora A. L. Sm. — Thallus squamulose, the 

 squamules thin, green, smooth, cither aproximate or scattered. 

 Perithecia black, large, prominent ; perithecial wall dimidiate ; 

 paraphyses few, filiform, interspersed with oily gi-anules ; ostiolar 

 filaments (periphyses) numerous ; spores 8 in the ascus, dark- 

 brown, ellipsoid, muriform, rather large, 0,035-48 mm. long, 

 0,020—30 mm. thick ; hymenial gelatine wine-red with iodine. — 

 Verrucaria peltophora Stirton in GrevUlea ui. p. 37 (1874) ; 

 Leight. Lich. Fl. ed. 3, p. 486. Specimen not seen. 



Hab. On the earth, Ben Lawers, Perthshire. 



108. THROMBIUM WaUr. Fl. Crypt. Germ. 1, p. 287 

 (1831) ; emend. Massal. Rio. lich. p. 156 (18-52). Inoderma 

 S. F. Gray Nat. Arr. i. p. 498 (1821) pro parte. Verrucaria 

 subgen. Inoderma Ach. Lich. Univ. p. 294 (1810). (Pi. 44.) 



Thallus cmstaceous, uniform, membranaceous, mucilaginous, 

 thin, sometimes developed within the substratum or altogether 

 wanting. Algal cells Pleurococcus. Perithecia simple, immersed 

 in the thallus or superficial, the outer wall of a carbonaceous 

 or horny stracture, light or dark-coloured, opening by a poriform 

 ostiole; paraphyses slender, branched, persistent; asci 4-8-spored; 

 spores ellipsoid, simple, colourless or brownish. 



The only British genus of simple-spored YerrucariacesB with 

 persistent paraphyses. Acharius's subgenus Inoderma represented 

 species of Vemu:aria with a somewhat soft thallus. S. F. Gray 

 raised it to generic rank and included in it two British species, 

 J. epigsa and I. hyssacea, the latter of doubtful position. 



1. Thr. lastevirens A. L. Sm. — Thallus forming a broadly 

 effused rather thick inseparable film, smooth, even, rather 



