PEZIZALES 



333 



number of female nuclei in each ascogonium always reaches several 

 hundred. The male nuclei group into a thick protoplasmic mass in 

 the vicinity of the tip of the trichogyne; the separating membrane is 

 dissolved and they migrate into the trichogyne (Fig. 220, 3). Mean- 

 while, the female nuclei in the ascogonium have been united to a central 

 hollow sphere, the septum in the trichogyne neck is temporarily dissolved, 

 the male nuclei migrate into the ascogonium and there, for the most 

 part, pair with the somewhat larger female nuclei. 



...anth 



an, 



Fig. 220. — Development of sexual organs of Pyronema confluens. 1. Tuft of ascogonia, 

 ascg, with trychogyne, tr, and antheridia, anth; P, sterile hyphae. 2. The nuclei of the 

 trichogyne degenerate; the antheridium is in open communication with the trichogyne. 

 3. The male nuclei migrate into the trichogyne; P, sterile hyphae which will develop the 

 paraphyses. 4. The basal wall of the trichogyne disappears, the male nuclei migrate 

 into the ascogonium which is already beginning to produce ascogenous hyphae, asc. h. 5. 

 The basal wall of the trichogyne again formed; nuclear pairing is completed and several 

 dicaryons have migrated into the ascogenous hyphae. (After Harper, 1900.) 



After a few hours, ten to twenty ascogenous hyphae grow out of the 

 ascogonium and take up the dicaryons (Fig. 220, 5). They branch very 

 much and the dicaryons increase by conjugate division (Fig. 221, 1) 

 Finally the ascogenous hyphae are broken up by septa so that two to 

 eight dicaryons are present in the vicinity of the ascogonium, and at a 

 distance from it, only one is present (Fig. 221, 2). Which nucleus of the 

 pair is female and which is male is not determinable, as their size differ- 

 ences have disappeared. 



