GEAPHIS] GEAPHIDACEJE 251 



becoming widei-, 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. eutypa, spathea and iremulans) ; 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). Opcgrapha serpentina Schrad. in 

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

 Graphis 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. tremulans). 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 UUacombe, near Bovey Tracey, Devon ; New 

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

 Forest, Grosfield, Codham Hall Woods, Hadleigh Woods and ToUes- 

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

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

 Ingleby Park and Airyholme Wood, Cleveland, Yorkshire ; Erthig 

 Wood, Denbighshire; near Glasgow, Lanarkshire; Castle Bernard 

 Park, Eostellan and Ballyedmond, Cork; Tore Mt., KiUarney ; 

 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. — Oromb. Lich. Brit, 

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

 Opegrapha pulverulenta Pers. in IJst. Ann. Bot. vii. p. 29 (1794)? 

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

 Nat. Arr. i. p. 502 1 G. serpentina var. radiata Leight. in Ann. 

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



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



Differs from the preceding variety in the thinner thallus and in 

 the expanded pruinose apothecia. 



Hub. On trees. — Distr. Eare throughout the British Isles. — B. M. 

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

 Hall, Hookleigh Woods, ToUeshunt d'Arcy and Little Waltham, 

 Essex ; near Worcester. 



