Rev. W. A. Leighton on the British Graphidese. 277 



The following varieties are noticeable : — 



a. minor. Lirellfe small. 



On beech. Tilgate Forest, Sussex ! Mr. Borrer. On aider, 

 near Little Malvern, Worcestershire ! Mr. E. Lees. 



T7iallus thin, tartareous, extensively cracked, somewhat pul- 

 verulent, the surface irregular, spurious thallodal margins nearly 

 or quite obliterated, pale dirty ashy gray, or pale yellow or pale 

 olive. Lirellne exceedingly numerous and crowded, very small, 

 short, broad and simple, varying in form from a mere roundish 

 dot to a small oblong or linear-oblong, or linear figure, very 

 obtuse and rounded at the ends, immersed, slightly prominent 

 above the level of the thallus, the shorter and smaller ones for 

 the most part straight, the longer ones more or less curved and 

 wavy, of a dark brown colour. Disk canaliculate, wide, open 

 and concave, even in a dry state, without pruina, when wet ex- 

 panded and flat, encompassed by the thin, prominent, more or 

 less waved proper margin. 



/3. major. Lirellse larger. 



On beech. St. Leonard's Forest, Sussex ! Mr. Borrer. 



Thallus very thin, subtartareous, even, extensively cracked, 

 bounded by a wavy irregular brown line, dull olive colour, raised 

 around the lirellse into a very narrow spurious margin. LirellfP 

 very numerous, not crowded but closely and pretty regularly 

 scattered over the whole thallus, much longer than in the pre- 

 ceding variety, slender and linear, very irregular and varied in 

 their disposition, slightly waved and curved, extremities obtuse 

 or obtusely pointed, or one obtuse and rounded, the other pointed, 

 immersed as in the last, but with a more distinct spurious mar- 

 gin, dark brown. Disk as in the last, canaliculate, open and 

 concave, without pruina, elevated and flat when wetted, sur- 

 rounded by the thin prominent wavy proper margin. 



7. radiata. Lirellae radiate. 



On ash ? Sussex ! Mr. Borrer. 



Thalhis in the centre moderately thick, tartareous, extensively 

 cracked, pulverulent, white, and raised around the lirellae into a 

 spurious white pulverulent margin, frequently more or less obli- 

 terated, thinner and not so pulverulent towards the wavy irre- 

 gular paler margins of the patch, which are destitute of lirellae. 

 Lirella very numerous and crowded, confined to the central por- 

 tion of the thallus, elongated, but varying in size, variously 

 branched, either simply or repeatedly, disposed more or less in a 

 somewhat radiate arrangement, linear and slender, of the same 

 width throughout, obtuse at the extremities, black. Disk rimae- 

 formi-canaliculate, narrow, more or less open when dry, expanded 



