Rev. W. A. Leighton on the British GraphidciE. 411 



Udlington near Shrewsbury, Shiopshii-e ! On elm, Batchcot, 

 Hey Forest near Ludlow, Shropshire 1 



Thallus thin, tartareous, cracked and uneven, somewhat pow- 

 dery, whitish or pale yellow, spreading indeterminately over the 

 rugged bark of trees. ArdeUcs very numerous and crowded, 

 covering nearly the whole thallus, and gi^'ing it at a little 

 distance a blackish pruinose aspect, vei-y variable in size and 

 shape, roundish or irregularly oblong, or othemise deformed by 

 conliuence, immersed, flat or slightly convex, brownish when 

 the pruiua is I'ubbed off, otherwise of a lead-colour, minutely 

 roughened on the surface, which is covered with a white pruina ; 

 in section pale and semitransparent, subgelatinous, enclosing 

 the asci which contain eight sporidia, of an obovate-linear or cla- 

 vate form, rounded at the extremity, generally 4-septate, some- 

 times 5-septate, and sometimes only 3-septate, pale yellow. 



Plate Till. fig. 35. a. Section of thallus and ardella ; &, sporidia; c, ascus 

 with sporidia. 



6. Arthonia ilicina, Tayl. Thallus thin, membranous, smooth, 

 shining, scaly, cream-colour, limited ; ardellse subimmersed, 

 scattered, irregularly rounded or oblong ; disk brownish-black, 

 plane, shining ; sporidia in asci, eight, very large, obovato-clavate, 

 6-septate, upper cell largest. 



Arthonia ilicina, Tayl. Fl. Hib. p. 2. 105 (1836). 



On holly. Cromeglown, Ireland ! Dr. Taylor in herb. Borrer. 

 Glengariff, Ireland ! Miss Hutchins in herb. Borrer. New Forest, 

 Hants ! Mr. Lyell in herb. Borrer. St. Leonard's Forest, Sussex ! 

 Mr. Borrer. 



T?cal/us thin, membranous, smooth, somewhat shining, scaly, pale 

 yellow or cream-colour, forming irregular patches 3—4 inches in 

 diameter, limited by an indistinct irregular browTi wavy watery 

 border variable in width. Ardella numerous, scattered, of a 

 large size, but with smaller ones interspersed, irregularly rounded 

 or oblong, their outline entire or slightly wa\T, half immersed 

 in the thallus, when dry flat, often cracked, curvmg up at the 

 margin as it were in loosening themselves from the thallus, 

 when wet convex and prominent. Disk plane, of a full brownish- 

 black, slightly shining. Lamina proligera pale brown, darker 

 brown on the surface, enclosing asci, each containing eight large 

 sporidia, obovato-clavate, 6-septate, the uppermost cell very 

 remarkably the largest. 



Opegrapha atra, tar. obscura, Schjer. Exsic. 517 ! is similar in 

 colour and general appearance, but the ardellae are smaller, closer 

 together and arranged in irregular parallelism, their outline 

 crenato-incised, their surface somewhat wrinkled, the sporidia 



