Rev. W. A. Leighton on the British Graphidese. 265 



and peeling oflf in thin scales, for the most part smooth and 

 shining, except here and there and about the lirellse, where there 

 are many minute irregular roundish elevations or granulations 

 more or less crowded, visible only under a lens, limited and cir- 

 cumscribed, when it comes into contact with other lichens, by an 

 irregular, waved, broadish pale black line or margin. Lirellce 

 scattered and distant, uplifting and bursting through the thallus 

 in a kind of irregular cleft, the thin upraised membrane of the 

 thallus forming a spurious thallodal margin by closely adhering 

 to and covering nearly the entire sides of the lirella, leaving only 

 the thin elevated proper margins visible and free, very slender 

 and narrow, simple or with a single branch, either about the 

 middle or at one extremity, if branched at the one extremity 

 then the lirella is furcate, if at the middle the branch is either 

 straight and at right angles to or curved and parallel with the 

 main body, straightish or variously curved, not uniform in any 

 one direction, but lying scattered irregularly and rather openly or 

 not crowded together, of a dull black, scarcely shining, generally 

 rather long, but variable in length, flexuose and wavy. Disk in 

 a dry state, rimseform, a mere simple deep chink. When wetted 

 all the parts expand, and the true form and habit of the lirella are 

 developed and disclosed. The thin elevated margins are then 

 seen to be in general closely approximated at one extremity of 

 the lirella, and to proceed so along the sides in a flexuose and 

 irregularly waved manner, now approaching, now separating 

 from each other, until approaching the other extremity they 

 form a lanceolate or linear-lanceolate expansion, more or less 

 marked and distinct, terminated by a very finely acuminate 

 point. The disclosed disk is in consequence variable in width 

 throughout the whole length, now a mere chink, now more or 

 less distinctly open and expanded, of a pale colour, naked and 

 never pruinose. 



yS. flexuosa. Lirellse elongated, simple or branched, flexuose. 



Lichen scriptus, HofFm. Enum. Lich. tab. 3. fig. 2 b. 

 Opegrapha pulcerulenta, Pers. Ust. Ann. st. 7- tab. 1. fig. 2 B. b, 

 Graphis scripta, jS. varia, Ach. L. Univ. 265 (1810). 



scripta, u. b. varia, Ach. Syn. 81 (1814). 



scripta, Ach., var. flexuosa, Leight. Lich. Brit. Exsic. 18 ! (1851). 



On oak and beech. Sussex ! Mr. Borrer. New Forest, Hamp- 

 shire ! Mr. Lyell. Loch Tay Woods ! Dr. R. K. Greville. Os- 

 westry, Shropshire ! Rev. T. Salwey. Gloddaeth near Conway, 

 Caernarvonshire ! 



Thallus thin and membranaceous, smooth and shining or mi- 

 nutely warty, as in the preceding, with which it assimilates also 

 in colour, though with a whiter or paler aspect. Some specimen* 



