HEMIASCOMYCETES 139 



When the septum between two gametangia is dissolved, a sexual 

 difference between the copulation branches begins to appear. Nuclei of 

 the male gametangium migrate into the female, whereby a male and a 

 female nucleus fuse in the gametangium near the copulation canal (Fig. 

 84, 2). The female gametangium develops an elongate tapering ascus 

 at the tip, while the male ceases development. The fusion nucleus which 

 was originally very large, undergoes several successive divisions whereby 

 the daughter nuclei gradually approach in size and appearance the super- 

 numerary original gametangial nuclei and finally may not be distinguished 

 from them (Fig. 84, 3 to 6). Each cuts out of the cytoplasm a large, 

 thick-walled ascospore while the non-functional gametangial nuclei 

 gradually degenerate (Fig. 84, 7). At maturity, the ascus opens at the 

 tip. The spores, with the rest of the protoplasm, are forced out and col- 

 lect before the opening as a slimy, sticky ball. They are capable of 

 immediate germination. As an exception, this development may take 

 place parthenogenetically where the gametangia develop asci without 

 fusion. 



The fertilization of Dipodascus is strikingly reminiscent of that of 

 Endogone. As in the latter, only one gametangial nucleus is activated 

 as a sexual nucleus; only, at least in Endogone pisiformis, the supernu- 

 merary unprivileged nuclei are pushed out of the gametangium, while in 

 Dipodascus they remain in the gametangium and only are resorbed in the 

 development of the ascus. Furthermore, the product of the sexual act is 

 a thick-walled hypnospore in Endogone while it is a sporangium in Dipo- 

 dascus. These differences may be explained, however, by the different 

 biological conditions of the two genera. Even the free cell formation of 

 Dipodascus can cause no difficulty in the conception. If the content of 

 the asci were divided by cleavage, as is always the case in the sporangium 

 of Endogone and other Zygomycetes, the unactivated gametangial nuclei 

 would survive in the spore. That can only be avoided if each daughter 

 nucleus of the fusion nucleus forms a membrane within its sphere and 

 leaves the unused protoplasm with the original vegetative nuclei as peri- 

 plasm. Hence it appears justifiable to seek the roots of the Dipodas- 

 caceae in the Zygomycetes with a life cycle of the type of Endogone. 



Endomycetaceae. — This family is often saprophytic on sugar con- 

 taining substrates, in the slime-flux of trees, the ambrosia fungi in the 

 borings of Coleoptera, more rarely parasitic in fructifications of Agari- 

 caceae and on man. Some of the species are used in Asia and Africa by 

 the natives as yeasts for fermentation. The best-known representatives 

 are Eremascus and Endomyces. In the former were originally placed the 

 sexual, in the latter the asexual forms; more recent investigations 

 have entirely destroyed these differences. 



As a starting point Eremascus fertilis on fruit juices (Stoppel, 1907; 

 Guillermond, 1909) should be mentioned. The hyphae are often branched 



