ASPERGILLACEAE 619 



1907; Domaradsky 1908). The helical ascoyoiiiiini divides into binucleate cells 

 which develop ascogenous hyphae. 



In Microascus trigonosporus (Emmons & B. (). Dodge 1931) the conidial 

 stage belongs in Scopulariopsis. The ascocarp originates from a coiled ascogo- 

 nium. Hyphae, which perhaps are antheridia, may be present or absent and 

 in any case are probably no longer functional. The ascogoninm becomes sur- 

 rounded by the hyphae of the developing perithecial wall and is carried up 

 until it occupies a position above the center of the maturing perithecium in- 

 stead of at its base as in most genera. The ascogenous hyphae, therefore, 

 grow downward as well as radially from the ascogonium. The asci arise as 

 lateral or terminal branches of the ascogenous hyphae. Crozier formation has 

 not been noted in this species. Eventually the asci deliquesce and the spores 

 are embedded in a gelified mass which is extruded from the mouth of tlie 

 perithecium. As the name implies, the spores are more or less tetrahedral in 

 this species. In M. intermedius, from decaying strawberry roots, development 

 is similar, although the conidial stage is unknown. Occasionally the tips of the 

 ascogenous hyphae are curved, but whether these perform the functions of 

 croziers as reported by Eraser [Gwynne-Vaughan] & Chambers (1907) for 

 Aspergillus herhariorum is unknown. Occasionally two or three ascogonia are 

 included in the same developing perithecium. In such a case, each group of 

 asci develops independently and may produce its own ostiole. 



In Thielavia terricola, apparently there is no trace of an antheridium, and 

 the ascogenous hyphae develop directly from the ascogonium. The asci de- 

 velop from croziers, Math typical fusion of the dicaryon of the penultimate cell 

 as is usual in the higher Ascomycetes. The ascogonium is located near the 

 middle of the perithecium, the radiating ascogenous hyphae are short. No 

 central cavity is formed but, as the asci develop, they destroy the tissue of the 

 interior of the perithecium. Thielavia Sepedonium, originally isolated as a 

 saprophyte from normal skin of the foot, follows the general tyi^e of Microascus 

 trigonosporus. The conidial stage belongs in the genus Sepedonium (Fig. 92, 

 4, 5) quite distinct from the usual type found in the Aspergillaceae. No an- 

 theridium is known (Fig. 92, ^-tS) ; the perithecium lacks an ostiole. The ascog- 

 enous hyphae are uninucleate except for the terminal cell, which is usually 

 binucleate (Fig. 92, 9). The ascus cell has only a single nucleus, the other 

 member of the dicaryon remaining behind in the supporting cell in the ascog- 

 enous hypha. Apparently no nuclear fusion occurs during the life cycle. The 

 usual nuclear divisions take place in the ascus, the chromosome number being 

 constantly four. A somewhat similar development has been reported in Peni- 

 cillium Brefeldianum by B. 0. Dodge (1933). 



Apparently sexuality has gradually degenerated with retardation and 

 ultimate elimination of the antheridium until in Thielavia Sepedonium and 

 Penicillium Brefeldianum there are no traces of an antheridium, no nuclear 

 fusions or reduction divisions in the life cycle. 



In most of the Aspergillaceae, perithecial formation is (|uite uniform. In 

 Aspergillus herhariorum, A. Fischeri, Penicillium Wortmanni, P. javanicum, P. 



