306 PYRENOCARPEl \ POLYBLASTIA 



Hub. On peaty earth between the squainulea of Dermatoca/rpon 

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

 locality). 



16. P. gothica Th. Fr. in Bot. Not. 1865, p. 112.— Thallus 

 thin, greenisli 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 

 pitupMoia Leight. Lich. El. p. 458 (1871) (fide Th. Fr. in K. 

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

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



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

 SphmHa. I have been unable to detect gonidia in Leighton's specimen, 

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



Hah. 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, either aproximate or scattered. 

 Perithecia black, large, prominent ; perithecial wall dimidiate ; 

 paraphyses few, filiform, interspersed with oily granules ; 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 Grevillea iii. p. 37 (1874) : 

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



Hab. On the earth, Ben Lawers, Perthshire. 



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

 (1831) ; emend. Massal. Ric. Lich. p. 156 (1852). Inoderma 

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

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



Thallus crustaceous, 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 structure, 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 Verrucariaceae with 

 persistent paraphyses. Acharius's subgenus Inoderma represented 

 species of Verrucaria with a somewhat soft thallus. S. F. Gray 

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

 I, epigsea and I. byssacea, the latter of doubtful position. 



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

 effused rather thick inseparable film, smooth, even, rather 



