VERRUCARIE.E. 51 



The perithecium is dimidiate, very much incurved at, 

 but not subtending the base of the nucleus, which is 

 separated from the stone only by a very thin black tunic 

 or internal lining. The extremely minute blackish dots 

 mentioned in E. Bot. Suppl. as occurring on the thallus, 

 appear under the microscope as little masses of light 

 brown semi-transparent resinous-looking globules, ulti- 

 mately becoming of a pale bluish-black colour and semi- 

 opaque. It is presumed these dots are Spiloma sphcerale 

 of Acharius and Hook. Br. FL, but surely rather a fungus 

 than a lichen. 



The peculiar incurved perithecium keeps this distinct 

 from both V. suhalhicanSy rupestriSy and immersa ; the 

 sporidia from V. Bufourii, 



ft Inner tunic pale y not black, 



25. V. DuFOURii, D,C, Sporidia in asci 8, broadly 

 oblong, uniseptate, granulate, pale. Plate XXI I. 

 fig. 4. 



Verkucaria DUFOURII, D. C. PI. Fr. ed. 2. ii. 318. (1805.) 



-_ Fries, L. Ref. 433. 



_ Borr. E. Bot. Suppl. 2791. 



Tayl. Fl. Hib. pt. ii. 92. 



Verrucaria pyrenophora. Ach. L. Univ. 285 (1810) ; Syn. 94. 



Cheddar ! Mr. Borrer. 



This and V, epipolcea have the largest apothecia 

 amongst the saxicolar Verrucarise. Th^ perithecium is of 

 a thick clumsy shape in section, deeply depressed at the 

 summit, incurved at the base. Nucleus pale brown, the 

 asci covering the basal portion, above which is frequently 

 a vacant space separating them from short minute fila- 

 ments fringing the upper portion ; the inner tunic is 

 darker brown and envelopes the nucleus. The sporidia 

 are large, ovate probably from compression, since they 

 not unfrequently are seen also of a regular elliptical or 

 oblong form, the internal granular contents large and 

 visible through the pale outer membrane. 



