REPRODUCTION. 623 



Pyronema, the reproductive organs are not developed in close 

 proximity to each other. In these Ascomycetes, which belong 

 to the Discomycetous Lichens (Collema, Synechoblastus 

 Leptogium, Physma), and to the Pyrenomycetes (Polystigma), 

 the antheridial filaments, termed sterigmata, are developed in 

 special receptacles, the spermogonia. The male cells are 

 formed by abstriction from the sterigmata; they are, like those 

 of the Florideae, non-motile cells provided with a cell-wall, and 

 are likewise termed spermatia. The female organ is a multi- 

 cellular hypha which forms a spirally wound basal portion 

 (ascogonium) and is prolonged into a straight portion, a 

 trichogyne (Fig. 73). Fertilisation is effected, as in the 

 Florideae, by the fusion of a spermatium with the trichogyne. 

 The product of fertilisation is the same as in Pyronema: the 

 fertilised ascogonium gives out hyphae which bear asci, and 

 these, together with sterile hyphae derived from the mycelium, 

 constitute a fructification. 



It is of interest to note the close correspondence between 

 the sexual process and the products of fertilisation of the 

 Ascomycetes, on the one hand, and of the Florideae, on the 

 other. In both cases there is no cell-formation in the female 

 organ which leads to the differentiation of one or more 

 oospheres ; and in both cases the product of the fertilisation of 

 the female organ is a many-spored fructification, each spore 

 (carpospore) being a sexually produced spore. 



Fig. 74 (after Baranetzky). Sexual reproductive organs of Ascobolus. 

 an antheridium. c ascogonium. 



In the Ascomycetes all stages of sexual degeneration are 

 represented. Some members of the group (e.g. the Erysipheae, 

 Ascobolus, Penicillium, etc.,) possess distinct sexual organs 



