VERRUCARIEiE. 53 



T// alius thill, uniform, very minutely cracked, at first 

 of a tawny olive, finally dark umber, or nearly black, 

 not unlike an old broAvn inky stain on the stones ; when 

 moistened the areolae look like minute, smooth, slightly 

 convex tawny scales. Apothecia very numerous and 

 crowded, minute, their apices generally protruded from 

 the thallus, hemispherical-conoid, black, somewhat shi- 

 ning. Perithechim dimidiate, not spreading at the base ; 

 nucleus white when moist, enclosed in a thin, dark 

 brown, inner tunic. 



The above characters will readily distinguish it from 

 other species with which it has hitherto been confounded. 

 V. umhrina locates itself on the stones in and about fresh 

 water lakes and streams, when it assumes much of the 

 general appearance of V. maura: but the specimens I 

 have seen in this apparently very old state are so friable 

 as to render all attempts at examination hopeless, and 

 without result. V, maura always affects the rocks or 

 pebbles on the sea shore, and is at once recognised by 

 the different nature and elevato- punctate appearance of 

 the thallus. 



28. V. coDONoiDEA, 710V. sj). Sporidia in asci 8, linear, 

 narrowed and rounded at each extremity, triseptate, 

 pale-yellow. Plate XXIII. fig. 3. 



Ilaughmond Hill, Shropshire ! Craig-y-Rhiw, parish 

 of Oswestry, Shropshire ! 



Thallus a mere film, scarcely discernible from the rock 

 upon which it grows. Apothecia hemispherical, papil- 

 late, prominent, very minute, dark-brown, resembling 

 the little bell of a clock in shape. Perithecium dimi- 

 diate ; nucleus white, enveloped in a very thin black or 

 dark brown tunic. 



Apparently distinct from V, margacea, in the size and 

 structure of the perithecium. Similar in general appear- 

 ance, but very much smaller, to states of V. mutahilis, 

 from which, moreover, the sporidia separate it. 



