268 Rev. W. A. Leightou on tlie British Graphidese. 



3. Graphis pulverulenta, Ach. Thallus thin, subtartarcous, 

 continuous, rugulose; lirellse subsessile, broadish, extremities 

 cuspidate ; proper margin thick, elevated, uniform ; thallodal 

 margin elevated, tumid ; disk broadly canaliculate, pruinose ; 

 sporidia eight, in asci, oblong or oval, margined, containing 8—10 

 horizontal rows of subrotund margined yellow spores. 



Opegrapha pulverulenta, Sm. E. Bot. 1754 (excl. syn.), the maguified figure 



excellent (1807). 

 Graphis pulverulenta, Ach. L. Univ. 266 (excl. syn. Pers.) (1810); Leight. 



Lich. Brit. Exsic. 20 ! 



pulverulenta, et. phlceodeSfWaWr. Crypt. Germ. 330 (in part) (1831), 



• scripta, i3. pulverulenta, Ach, Syn. 82 (excl. sj-n. Pers.) (1814). 



scripta, Sprengel, Syst. Veg. 4. pt. 1. 2.52 (in part) (1827). 



Opegrapha scripta a. Fries, L. Ref. 371 (in part, inasmuch as he quotes 



Ach. L. Univ. and E. Bot. fig. I have not seen his Lich. Suec. Exs. 



no,33& 124) (1831), 

 scripta. Hook. Br. Fl. 2. 147 (in part) (1833) ; Tayl. Fl, Hib. pt. 2. 



106 (in part). 



On oaks. Sussex ! Mr. Borrer. Hartshill Wood near Athef- 

 stone ! Gopsall Wood ! Leicestershire ! Rev.A.Bloxam. Bangor ! 

 Montalto ! Cultra ! Co. Down, Mr. W. Thompson. Barmouth ! 

 Rev. T. Salwey. On poplar, near the Berrow, southern end of 

 Malvern Hills, Worcestershire ! Mr. E. Lees. Donnington Park, 

 Leicestershire ! Rev. A. Bloxam. Blarney, Cork ! Mr. I. Carroll. 

 Gloddaeth near Conway, Caernarvonshire ! 



Thallus effuse, in some instances very thin and membranous, 

 of a pale dull ashy yellow or cream-colour, thickened and swollen 

 about the lirellse, minutely verruculose ; in other instances be- 

 coming much thicker, subtartareous, swollen into upraised irre- 

 gular rugosities, cracked, the small portions of even surface 

 smoothish and cream-coloured. In other cases, probably from 

 age, becoming very thick, tartareous, pulverulent, very rugged 

 and rough with upraised crowded rugosities, extensively and 

 variously cracked, either whitish or cream-coloured, or of a dull 

 darkish gray hue. In a few instances quite thick, tartareous, 

 pulverulent, even, continuous, and almost quite white. LirellcB 

 generally crowded, exceedingly variable in size, shape and direc- 

 tion, curved into all sorts of forms, simple, or branched either at 

 right angles or in a divaricate and subradiate manner. Under 

 all circumstances and forms, however, maintaining this one uni- 

 form and constant character and habit. The lirella appears to 

 be upraised and laid sessile upon or amid the tumid thallodal 

 margins which are thrown fully back, disclosing the entire bold 

 prominent lirella, which is broadish, nearly uniform in width 

 throughout, terminating at each extremity in an acute point, 

 very frequently with a peculiar curve which gives it much of a 



