IV] 



PEZIZALES 



105 



While the formation of the pore is in progress the nuclei of the tricho- 

 gyne degenerate, and, by the time that they are completely disorganized a 

 migration of the male nuclei through the pore begins. Ultimately the 

 contents of the trichogyne degenerate still further, till the cytoplasm and 

 nuclei together form a densely staining mass which may be recognized even 

 in the mature fruit. The male nuclei continue to pass into the tube until it 

 is densely filled, and sometimes a trifle swollen. According to most observers 

 the wall at the base of the trichogyne now breaks down so that an open 

 passage is formed and the male nuclei travel through (fig. 63 a), and mingle 



Fig. 63. Pyronema confluens; a. entrance of male nuclei into oogonium, x 1435; b. association of 

 male and female nuclei, x 1160; c. ascogenous hyphae with nuclei in pairs, x82o; after 

 Claussen. 



with the female nuclei. After their migration is complete a fresh wall is 

 laid down across the base of the trichogyne, cutting off the oogonium once 

 more as a single spherical cell. 



The female nuclei meantime become aggregated together (fig. 620) and 

 form a hollow sphere or dome or a sickle-shaped group. This is no doubt 

 a provision for insuring their association with the male nuclei with the 

 greatest certainty and dispatch. 



According to both Harper and Claussen, the sexual nuclei now pair; 

 Harper has recorded complete fusion at this stage (fig. 62 b}, while Claussen 

 (fig. 63 b} regards the nuclei as merely associated in preparation for their 

 ultimate union in the ascus. Dangeard. on the other hand, denies the dis- 

 appearance of the wall between the oogonium and trichogyne or the passage 

 of the male nuclei beyond the latter organ, and Brown has described a 

 variety in which the trichogyne and antheridium fail to unite. 



