THELOCARPON] THELOCARPACEiE 347 



hymenial gelatine not tinged, the asci tawny-reddish with iodine. 

 — Cromb. Lich. Brit. p. 107; Leight. Lich. Fl. p. 407; ed. 3, 

 p. 439. Specimen not seen. 



Allied to the Lapland species, Tli. epiholuyn Nyl. I. c, but differing 

 in the slightly larger spores and stouter paraphyses. Leighton 

 referred to it in Ann. Mag. Nat. Hist. ser. 8, xiv. p. 402 (1864), but 

 did not then discriminate between it and Th. Laureri. 



Hah. Parasitic on the thalius of Bceomyces rufus in an upland 

 hilly district (Sfciperstones Hill, Shropshire). 



TRYPETHELIACE^, 



Thalius crustaceous, not corticated, superficial or developed 

 under the bark (hypophlauodal), sometimes almost obsolete. Algal 

 cells (gonidia) Trentepohlia. Perithecia united in a stroma, each 

 with a separate ostiole ; spores 2-8 in the ascus, septate, colour- 

 less or brown. 



The Order is well represented in tropical and subtropical regions ; 

 there is only one British genus. 



121. MELANOTHECA Fee Ess. Crypt. Suppl. p. 70 (1837); 

 emend. Nyl. in Maine et Loire Mem. Soc. Acad. iv. p. 69 (1858). 

 (PI. 57.) 



Thalius forming spots on the substratum or scarcely visible. 

 Perithecia several confluent in a stroma, the inner dividing walls 

 more or less distinct, the upper common wall black ; paraphyses 

 present, confused or distinct ; asci usually 8-spored ; spores 

 elongate, 1- many-septate, colourless or coloured. 



Mueller-Argau (in Engl. Bot. Jahrb. vi. p. 376 (1885) ) has limited 

 the genus to include only species with coloured spores. As here 

 understood it includes species with spores either colourless or 

 coloured. 



1. M. gelatinosa Nyl. in Mem. Soc. Sci. Nat. Clierb. v. 

 pp. 140, 145 (1857), emend. — Thalius forming pale or brown 

 spots on the bark, usually determinate with a dark line at the 

 circumference. Perithecia many in a roundish flat black stroma, 

 dotted with the ostioles ; perithecial walls brownish or almost 

 colourless, not distinct at the base ; paraphyses indistinct, some- 

 what crushed ; asci obpyriform ; spores oblong-ellipsoid, blunt 

 at the ends, colourless becoming brownish, 0,023-27 mm. long, 

 0,007-' 010 mm. thick; hymenial gelatine not tinged, the asci 

 yellowish-red, with iodine. — Jones in Proc. Nat. Hist. Soc. 

 Dublin 1864, p. 129; Cromb. Lich. Brit. p. 123; Leight. Lich. 

 Fl. p. 466 ; ed. 3, p. 498. Arihonia gelatinosa Chev. in Journ. 

 Phys. Chira. Hist. Nat. Paris xciv. p. 54 (1822). 



Exsicc. Mudd n. 232 & Leight. nos. 223 (as Arfhonia puncti- 



