258 GBAPHIDEI f ESTEROGRAPHA 



CHIODECTONACE^. 



Thallus crustaceous. Algal cells usually TreniepoUia. Apo- 

 thecia aggregate in specialized prominent stroma-like portions of 

 the thallus (veiTUca;), deeply immersed, inimarginate, small and 

 punctiform or elongate ; asci elongate-clavate ; spores elongate, 

 plariseptate. 



Characterized by the differentiation of the thaUas and by the 

 arrangement and form of the apothecia. The order is well-represented 

 in tropical countries ; in Great Britain there are only a few species 

 which are contained in the following genera : — 



Apothecia immarginate. 



Hypothecium colourless or thinly black. 



Spores colourless 94. Enterographa. 



Spores brown 95. Selerophyton. 



Hypothecium thick and black 96. Chiodecton. 



Apothecia marginate 97. Glyphis. 



94. ENTEROGRAPHA Fee Ess. Ciypt. p. xxxii. (1824). 

 Stigmatidium Meyer Enfcw. Met. Fortpfl. Flecht. p. 328 (1825). 

 Platygramma Leight. in Ann. Mag. Nat. Hist. ser. 2. xiii. p. 393 

 (1854) pro parte (non Meyer). (PI. 31.) 



Thallus crustaceous, thickish, limited by a black hypothallns. 

 Algal cells TrentepoMia. Apothecia aggregate or contiguous in 

 lines or soKtary, roundish or shortly elongate, immarginate, 

 deeply immersed in the verruca; hypothecium colourless or 

 thinly black ; paraphyses slender, branched ; asci clavate, 

 8-spored ; spores elongate-fusiform, colourless, pluriseptate. Sper- 

 mogones with cylindrical elongate or elliptical straight or bent 

 spermatia. 



The deeply immersed fructifications are occasionally somewhat 

 perithecial-Uke in form and structure, especially when the disc is 

 contracted to a small opening. The graphideine character is more 

 apparent in those species that have elongate apothecia. 



1. E. crassa Fee op. cit. pp. xxxii. & xc. t. 1, f. 6 (1824). — 

 Thallus thick, greyish-white, olivaceous or brownish, smooth and 

 polished, becoming somewhat cracked, limited and often inter- 

 sected by the blackish hypothallus , the verrucse flat, wide- 

 spreading not prominent. Apothecia brownish-black, minute, 

 numerous, punctiform, solitary or aggregate in flexuose lines, or 

 in small groups, deeply immersed in the thallus, immarginate ; 

 hypothecium colourless ; spores fusiform-elongate, 5-7-septate, 

 0,024—35 mm. long, 0,005 mm. thick ; spermogones with short 

 rod-Jike spermatia 0,004r-5 mm. long, 0,001 mm. thick. — Opegrapha 

 crassa DC. Fl. Franc, ii. p. 312 (1805). Lichen obscurus Sm. 

 Engl. Bot. t. 17.^2 (1807) pro parte (non Ach.). Stigmatidium 

 cra^sum Dub. Bot. Gall. ii. p. 643 (1830) ; JIudd Man. p. 245 ; 



