86 TEXT-BOOK OF FUNGI 



pass into the oogonium. Previous to the passage of the male 

 nuclei into the oogonium, the nuclei in the latter become 

 massed in the centre, and after the entry of the contents of 

 the antheridium, the male and female nuclei fuse in pairs. 

 These paired nuclei do not afterwards fuse into a single 

 mass. After fertilisation the oogonium, or now the asco- 

 gonium, produces ascogenous hyphae, into which the fused 

 nuclei pass. As in Erysiphe, the penultimate cell of each 

 ascogenous hypha contains two nuclei which fuse. This 

 cell then becomes an ascus. The ascocarp in Pyronema is 

 a compound body, the asci originating from several fertilised 

 oogonia produced in a cluster. 



The sexual process in Pyronema agrees in essential points, 

 and is homologous with that in other Ascomycetes, as 

 Sphaerothecci) Erysiphe^ Peziza, Ascobolus^ etc., and also with 

 that of some algae, as Nemalion, Batrachospermum, etc. 



According to Barker, numerous nuclei are present in the 

 antheridium and oosphere of Monascus. 



The most perfect form of sexual reproduction where a 

 trichogyne is present is met with in the Laboulbeniaceae, 

 belonging to the Ascomycetes. Our knowledge of this 

 interesting group is due to the researches of Thaxter. 



The fundamental structure in these minute fungi, which 

 rarely attain to i mm. in height, is simple, the receptacle 

 often consisting primarily of two cells ; the apical cell gives 

 origin to the branches or appendages bearing the antheridia 

 or male organs, whereas the basal cell, after repeated 

 division, produces the procarp or carpogenic cell, sur- 

 mounted by the trichogyne. The trichogyne may consist 

 of a single cell, or a much-branched, septate body, con- 

 sisting of many cells. The free tips of the trichogyne are 

 alone receptive, and conjugate with the antherozoids 



