PHACIDIUM. 387 



Order VIII. PHACIDIACEJE. 



Receptacle immersed, more or less coriaceous ; hyme- 

 nium at first covered, at length exposed by the regular 

 or irregular fissure of the outer covering (Plate XII. 

 figs. 76-78.) 



Name From the typical genus Phacidium. 



ARRANGEMENT OF THE GENERA. 



I. Phacidium. Fries. I III. Stegia. Fries. 



II. Trochila. Fries. 



KEY TO THE GENERA. 



Hymenium becoming exposed by the epidermis of 



the matrix splitting from the centre into lacmise Phacidium. 



Hymenium becoming exposed by splitting at the 



summit irregularly . . . . . . . . . . Trochila. 



Hymenium becoming exposed by the falling off of 

 a horizontal operculuin . . . . . . . . Stegia. 



GENUS I. PHACIDIUM. Fries. 



Perithecium orbicular, flattened, subclimidiate, de- 

 hiscing from the centre into lacini?e, distinct from the 

 placentiform disc. (Plate XII. fig. 76.) 



The perithecium is covered by the epidermis of the 

 matrix ; the hymenium is mostly dark-coloured, lining 

 the base of the perithecium. 



On leaves and bark. 



Name <aco, a lentil, c?or, resemblance ; shaped 

 like a lentil. 



ARRANGEMENT OP THE SPECIES. 



A. Sporidia elliptic or subelliptic. 



(a i Brown . . . . . . . speoies 1 



(?>) Hyaline . . . . . . . . 2-6 



B. Sporidia fusiform or subfusiform .. 7-10 

 c. Sporidia filiform or subfiliform . . . . 11-16 



KEY TO THE SPECIES. 



On trees and shrubs . . . . . . . . 1 



On herbaceous plants . . . . . . . . . . 4 



On the stems . . . . . . . . . . . . 2 



On the leaves . . 3 



