ENDOMYCETALES 137 



Ascoideaceae. — In Ascoidea rubescens in the slime flux of trees, the myce- 

 lium is coenocytic, septate, and branched. The mycelium produces conidia 

 either singly or in tufts. The gametangium is a large multinucleate cell. 

 Varitchak has reported the degeneration of all but one pair of nuclei, which 

 proceed to fuse. Walker (1935) was unable to confirm this statement and 

 suggests that the "privileged sexual nuclei" of Ascoidea are degenerating 

 nuclei which she has also seen in other parts of the fungus. By two or three 

 successive divisions the spore initials are cut out of the mass as lenticular, 

 uninucleate portions of the protoplasm. Finally, these spore initials contract 

 and form the typical cucullate spores of this series. Not all of the protoplasm 

 is used up in the process, some remaining behind as the epiplasm, as in other 

 groups of Ascomycetes. The ascospores are extruded from the mouth of the 

 ascus by the proliferation of the cell next below it. This proliferating cell 

 proceeds to form another ascus at the same site. Plasmogamy occurs shortly 

 after spore germination, but the occurrence of caryogamy is still uncertain. 

 The spore sac appears similar to the gametangium of Spermophthora, but 

 gametes are not differentiated and whether there is nuclear fusion in this 

 organ is still questioned. In its later stages the organ behaves as a multi- 

 spored ascus, although ontogenetically it bears little relation to such a 

 structure. The proliferation of the basal cell into the mature organ sug- 

 gests sporangial proliferation in the Saprolegniaceae, but the manner of 

 spore formation is entirely different. It would seem likely that we are 

 dealing with a stage of degeneration from an ancestral form like Spermoph- 

 thora in which the gametangium has ceased to function as such and func- 

 tions as an ascus with a shortening of the stages between gametangium and 

 ascus and with a partial or complete elimination of the sexual act. The fact 

 that the spore initials appear similar to the ascospores of Spermophthora and 

 finally become cucullate as in the Endomycetaceae, suggests that it may be 

 an intermediate stage in the phylogeny of the latter. 



Endomycetaceae.- — In this family the mycelium is usually uninucleate, soon 

 degenerating to sprout mycelium, conidia are no longer differentiated, the 

 ascospore has become reduced in number per ascus and has assumed a cucul- 

 late or saturnine shape. 



So far as is known this family is saprophytic, although Hansenula has occa- 

 sionally been isolated from sputum, and Pijper (1928) reports Hanseniospora 

 from a case of onychomycosis. The strains of fungi from these isolations have 

 not been reported pathogenic for experimental animals. It is possible that 

 they may cause irritation in the mucous membranes or aggravate a condition 

 primarily due to some other organism, but reports of the cases should be 

 scrutinized very carefully before admitting them as pathogens. On the other 

 hand, there is a large group of parasites previously referred to Endomyces, 

 having spherical to ellipsoid, smooth spores, which is here treated in the 

 Eremascaceae. 



