112 



DISCOMYCETES 



[CH. 



Humaria granulata is a common red or orange coprophilous form. The 

 archicarp develops as a side branch from an ordinary hypha. The apical 

 cell of this branch increases in size and becomes spherical, forming the 

 oogonium (fig. 6^) ; it contains large numbers of well-marked nuclei. When 

 it is full grown the oogonial nuclei fuse in pairs (fig. 68 a), and the fusion 

 nuclei pass into the ascogenous hyphae (fig. 68 b). There is no sign of either 

 trichogyne or antheridium. 



Fig. 68. Humaria granulata Quel. ; a. fusion of nuclei in oogonium, x 3200 ; b. oogonium 

 giving rise to ascogenous hyphae, x 1250; after Blackman and Fraser. 



Vegetative cells grow up and invest the archicarp, forming a close 

 pseudoparenchymatous sheath in which the ascogenous hyphae ramify. 

 They give rise at last to asci in the usual way. 



Four chromosomes have been recorded in the ascogenous hyphae, 

 eight in the first division in the ascus and four in the two subsequent 



