FUNGI. 



^57 



mycelium, although the conjugation itself was not observed and the mode of origin of 

 the asci remained doubtful. It is nevertheless certain that the receptacles of the last- 

 named Pyrenomycetes are developed from an apparatus similar to the sexual organ 

 of Eurotium and Erysiphe ; and earlier statements of Fuisting contain at least indications 

 that in other Pyrenomycetes also the perithecia may be the result of a sexual process. 



Since the development of the Fungi belonging to this section undergo important 

 modifications in the different genera, a comprehensive description would be altogether 

 wanting in lucidity. I prefer therefore to explain the most important points in two very 

 different examples. 



One of the simplest of the Pyrenomycetes is Eurotium repens (Fig. 179); and but 

 very slightly dilFering from Eurotium is Aspergillus glaucus, the history of whose de- 



FlG. 179— Development of Eurotium "efens (after De Barj'). A small portion of a mycelium, with the conidia-bearing^ 

 liypha; c and young ascogonium as; B tlie spiral ascogonium as with the antheridium /; C the same, beginning to be 

 surrounded by the threa<ls out of which the wall of the peritheciMm is formed; D a perithecium ; E, F section of young^ 

 perithecia, -w parietal cells, y pseudo-parenchyma, as ascogonium ; G an ascus; //an ascospore. 



velopment has been described in detail by De Bary. Both species are found on the most 

 various decaying or dead organic bodies, and are especially abundant on preserved fruit. 

 The Fungus makes its appearance as a fine flocculent white mycelium overspreading 

 the surface, from which the upright conidia-bearing hyphae soon rise in large numbers. 

 These swell in the upper part into a globular form, and on the upper half of the 

 globe give rise to a number of peg-shaped projections, densely crowded and arranged 

 radially, the Sterigmata, each of which produces gradually a long chain of greenish 

 spores ; so that finally the head of the receptacle is covered by a thick layer of them. 

 During this formation of conidia, the sexual organs appear on the same mycelium. The 

 female organ, called by De Bary the Ascogonium or Carpogonium, is the corkscrew-like 

 end of a branch of the mycelium (Fig. 179, A, as), the coils of which become gradually 



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