116 



ASCOMYCETES 



123 a : 124 &). The conidiophores bear no analogy to the basidia. 

 [The question of the occurrence of sexual reproduction among 

 the Ascomycetes has been much disputed. Eepently Harper has 

 proved the fusion of a male and female nucleus in Sphcerotheca 

 (see page 120), and also in Pyronema, a 

 Fungus closely allied to Peziza. In Py- 

 ronema both the oogonium and antheri- 

 dium contain several nuclei. The 

 ** former is a large cylindrical cell having 

 the apex prolonged into a trichogyne? 

 which is also multinucleate. The latter 

 is a cylindrical cell which originates 

 below the oogonium, its apex coming 

 into close touch with the tip of the 

 trichogyne. The intervening wall is 

 absorbed at the point of contact, &nd 

 the male nuclei then pass into the 

 trichogyne, and finally, entering the 

 FIG. 102A. Sphcerotheca castag- oogonium by the breaking down of the 



net: A Ooeronium (o) and anthe- .. ' i 



ridium (a);jBthetrneantheridium separating wall, the male nuclei conjugate 

 in pairs with the female nuclei of the 

 oogonium. The oogoniumis now cut 

 a new cell-wall formed at the 



Harperf enclosing base of the trichogyne, and sends forth 

 ascogenous hyphee containing the conju- 



Fio. 102s. Pyronema confluent : A Rosette of three pairs of sexual cells drawn from 

 surface view; B section ot! an oogonium, ascogenous liyphse containing nuclei growing 

 out from the ooifonium ; new partition wall has formed at tlie base of the trichogyne; C 

 semi-diagramatic drawing of a section of an ascocarp in which the first asci are ripening. 

 a Antheridium ; og oogonium; as/ ascogenous hypnte ; ascasci; t trichogyne. 



