274 Rev. W. A. Leighton on the British Graphideae. 



Opegrapha scripta, a. limitata, B. Schser." seem identical with 

 our plant. " No. 89. Opegrapha scripta v. pulverulenta, Ach." 

 is again the same thing, but in an older state, with the disk 

 broader and more expanded, approaching the eutypa form. In 

 " ed. alt. immut." No. 89 is similar to No. 89 of the 1st ed., 

 but No. 87 is our var. divaricata, and No. 88 is a form of our 

 G. diffracta, much resembling the specimen on beech of 

 "No. 91. Opegrapha scripta, e. serpentina, A. Schser." in Mr. 

 Borrer's copy of the 1st ed., which is also referable to G. dif- 

 fracta ; whilst No. 91 of " ed. alt. immut." differs from No. 91 

 of the 1st ed., being rather referable to eutypa. The sporidia 

 prove the identity of all of them to Cr. serpentina. 



Mr. Borrer's herbarium contains a miserable morsel from 

 Acharius of his variety spathea, which does not however accord 

 with the description in ' Lich. Univ/ and ' Syn.,' but with which 

 our British specimens agree pretty well. 



The variety spathea is not unlike some states of G. diffracta in 

 general external appearance, but is distinguished from that by 

 the nature and structure of the thallus. 



K. tremulans. Lirellse peculiarly tremulous in their outline. 

 Graphis serpentina, var. tremulans, Leight. Lich. Brit. Exs. 22 ! (1851). 



On ash. Sussex ! Mr. Borrer. Killarney ! Mr, W. Thompson. 

 Gopsall Wood, Leicestershire ! Rev. A. Bloxam. Cors-y-gedol ! 

 Rev. T. Salwey. Chelmsford, Essex ! Mr. H. Piggot. Pentre- 

 gaer near Oswestry ! Weir Coppice near Shrewsbury ! 



Thallus thin, subtartareous, cracked here and there, more or 

 less roughened with minute tubercles and rugosities, pale ashy 

 yellow or ashy gray, scarcely raised around the lirellse, the spu- 

 rious margin being obliterated. LzVe//« elongated, chiefly simple, 

 some branched or furcate at one extremity, or from the middle, 

 curved and waved in all directions, giving the general appear- 

 ance at a little distance of a coarse irregular network thrown 

 over the bark, elevated above the thallus, extremities very obtuse. 

 Disk narrow, but widely canaliculate when dry, when wet more 

 expanded, pale and subpruinose, surrounded by the proper mar- 

 gin which is narrowly edged, excessively waved and crisped, and 

 by its irregular contractions and dilatations giving to the lirellse 

 a peculiar tremulous aspect. 



\. eutijpa, Ach. Lirellse with a very broad densely pruinose 



disk. 



Opegrapha serpentina, Sm. E. Bot. 1755 (1807). 



serpentina, e. eutypa, Ach. L. Univ. 270 (1810); Syn. 84. 



Graphis pulverulenta, Moug. & Nestl. Stirpes, 361 ! (1813). 



On oak, beech and ash ? Ardiugley ! St. Leonard's Forest, 



