ORAPHIS] GRAPHIDACE^ 251 



becoming wider, sometimes subpruinose ; margins thin, elevated, 

 often crisp and wavy, the thallus usually forming an outer white 

 margin. — Cromb. Lich. Brit. p. 96 ; Leight. Lich. Fl. p. 365 

 (incl. fF. eutypaj spathea and tremulans) ; ed. 3, p. 429 (incl. fF.) ; 

 vars. radiata (non Leight.), spathea, tremulans, eutypa and diffracta 

 Mudd Man. pp. 238-240 (1861). Lichen serpentinus Ach. Lich. 

 Suec. Prodr. p. 25 (1798). Opegrapha serpentina Schrad. in 

 Schrad. Journ. Bot. 1801, i. p. 79 [1803]; Engl. Bot. t. 1755? 

 Oraphis serpentina Ach. Lich. Univ. p. 269 (1810) pro parte 

 (incl. vars. spathea and eutypa, p. 270; var. rugosa, p. 271); 

 S. F. Gray Nat. Arr. i. p. 502 ; vars. spathea, tremulans and eutypa 

 Leight. in Ann. Mag. Nat. Hist. ser. 2, xiii. pp. 273 & 274 

 (1854). G. diffracta Turn, ex Leight. I c. p. 276, t. 6, f. 21 

 (incl. vars.). 



Exsicc. Leight. nos. 22, 340; Mudd nos. 218, 219, 220, 222. 



Chiefly characterized by the superficial whitish thallus, and almost 

 specifically distinct in the extreme forms. When it is thick and 

 tartareous with the apothecia deeply immersed it is f. eutypa ; with a 

 thinner thallus the apothecia become more prominent and have either 

 rather thick straight margins (f. spathea) or excessively wavy and 

 tremulous ones (f. tre7nulans) . The disc is usually rather narrow, 

 though there are intermediate forms with a wider pruinose disc that 

 connect it with var. pulverulenta. 



Hah. — On trees. — Distr. Fairly common throughout England and 

 S. W. Ireland ; rarer in Scotland. — B. M. Withiel, Cornwall ; near 

 Lustleigh, Torquay and Ullacombe, near Bovey Tracey, Devon ; New 

 Forest, Hants ; Hurst, Balcombe and Ardingly, Sussex ; Epping 

 Forest, Gosfield, Codham Hall Woods, Hadleigh Woods and Tolles- 

 hunt d'Arcy, Messing, Essex ; Abdon and near Shrewsbury, Shrop- 

 shire ; Malvern, Worcestershire ; Yarmouth, Norfolk ; Newton Wood, 

 Ingleby Park and Airj^holme Wood, Cleveland, Yorkshire ; Erthig 

 Wood, Denbighshire ; near Glasgow, Lanarkshire ; Castle Bernard 

 Park, EosteUan and Ballyedmond, Cork; Tore Mt., Killarney ; 

 Killaloe, Clare ; Glenstale, Tipperary. 



Var. pulverulenta Ach. Syn. p. 82 (1814). — Thallus super- 

 ficial, whitish, effuse, thinner than in the preceding species. 

 Apothecia emerging, rather long and curved ; margins thickish, 

 elevated ; disc becoming plane and pruinose, — Cromb. Lich. Brit, 

 p. 96 ; Leight. Lich. Fl. p. 367 (incl. f. radiata) ; ed. 3, p. 430. 

 Opegrapha pulveridenta Pers. in Ust. Ann. Bot. vii. p. 29 (1794)? 

 Gr aphis pulverulenta Ach. Lich. Univ. p. 266 (1810) ; S. F. Gray 

 Nat. Arr. i. p. 502 ? G. serpentina var. radiata Leight. in Ann. 

 Mag. Nat. Hist. ser. 2, xiii. p. 272 (1854). 



Exsicc. Larb. Lich. Caesar, n. 87. 



DifTers from the preceding variety in the thinner thallus and in 

 the expanded pruinose apothecia. 



Hah. On trees. — Distr. Rare throughout the British Isles. — B. M. 

 Jersey ; Tregawn, Withiel, Cornwall ; Lustleigh, Devon ; Codham 

 Hall, Hockleigh Woods, Tolleshunt d'Arcy and Little Waltham, 

 Essex ; near Worcester. 



