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



have the thallus irregularly raised into verrucse or rugosities, 

 and become white and pulverulent. Others again are so de- 

 cidedly rugged all over, that the lirellse appear seated on thick- 

 ened upraised irregularly wavy rugosities, white and pulverulent 

 or ashy gray : this latter is supposed to be that of great old age, 

 or resulting from some peculiar circumstances which render the 

 thallus thus thick and tartareous. The lirellce are very long, 

 curved, flexuose and wavy in every form and fashion, either quite 

 simple, or with a single branch at one extremity, or sometimes 

 branched at both extremities, distinct and separate, or curving 

 and anastomosing and running one into the other, narrow or 

 various in breadth. 



Some specimens on beech from the New Forest had the lirellse 

 so very much elongated and so slender, curved, flexuose and 

 wavy, simple and variously branched, as to render it probable 

 that they may be referable to Graphis scripta, e. tenerrima, Ach. 

 L. Univ. 266 and Syu. 82. 



7. radiata. Lirellse dendritically radiate. 



Sussex ! Mr. Borrer. Rammerseales, Dumfriesshire ! Cultra, 

 Co. Down ! Mr. W. Thompson. 



Thallus thin, membranous and shining as in the last, but the 

 granulations or minute rugosities rather more numerous, and 

 slightly white or pulverulent about the lirellse. Lirella either 

 scattered or approximate, but not crowded, each consisting of 

 five, six, or more slender, flexuose, wavy, rather elongated mem- 

 bers, separate but radiating from a common centre, in a den- 

 dritic manner subdichotomously branched, each branch ulti- 

 mately terminating in a linear-lanceolate elongated acuminate 

 expansion ; sometimes however the ultimate branches are shorter 

 and more rigid, terminating in an obtuse wide-spreading fur- 

 cation. The wavy character of the thin proper margins, the 

 naked, not pruinose, rimseform, more or less expanded disk, and 

 the general habit of the lirellae as in the preceding varieties. 



8. divaricata. Lirellae divaricately branched. 



Lichen scriptus, Hoffm. Enum. t. 3. f. 2 a. 



Graphis scripta, b. hebraica, Ach. L. Univ. 266 (1810). 



scripta, ec. d. hebraica, Ach. Syn. 82 (1814). 



Opegrapha scripta, Johnston! Fl. Berw. 2. 100 (1831). 



Graphis scripta, Ach., var. divaricata, Leight. Lich. Brit. Exsic. 19! (1851). 



Sussex ! Mr. Borrer. Bangor, Co. Down ! Mr. W. Thompson. 

 Rae Hill Woods ! Dr. R. K. Greville. Castle Bernard Park, Ban- 

 don, Ireland ! Rev. Prof. Hincks. Berwick-on-Tweed ! Dr. G. 

 Johnston. Gloddaeth, near Conway, Caernarvonshire ! 



Thallus thin and membranous, sometimes quite smooth. 



