HEMIASCOM YCETES 



145 



In addition to this usual course of development, there occur also 

 numerous variants; thus, the male copulation branch may approach 

 the female at the side instead of the tip (Fig. 89, 8); or the copulation 

 branches may contain only a single nucleus with no ab junction of the 

 stipe cell; or the female gametangium may develop parthenogenetically 

 without copulation (Guillermond, 1909). 



In Endomyces decipiens, which is also characterized by the type of 

 cell multiplication but contains uninucleate cells, sexual organs are 

 almost entirely absent (Brefeld, 1891; Dangeard, 1907; Juel, 1921). It 

 is parasitic on fructifications of Armillaria mellea and fruits in the lamellae. 

 The asci arise on the hyphae as small branches which swell into sacs and 



Fig. 90. — Endomyces decipiens. Development of asci. ( X 800; after Juel, 1921.) 



are abjointed from the hypha. As a rare exception, a sexual act takes 

 place (isogamously!). Although occasionally three nuclear divisions 

 occur in the asci, they always contain only four spores which, as in E. 

 fibuliger, cucullate. In cultures, the hyphae break up into uninucleate 

 oidia. On branches they form thick-walled, yellowish gemmae the 

 size of asci which, under suitable conditions, germinate with one or 

 more germ tubes. E. decipiens has reached the same height as E. 

 javanensis and E. capsidaris in the isogamous series. 



Let us review the course of presentation. The Endomycetaceae 

 contain some forms with completely developed sexuality, such as Eremas- 

 cus fertilis and the heterogamous Endomyces Magnusii. Their life 

 cycle may be illustrated as follows: 



I PC. R 



Mycelium— »Gametangia-+Ascus— >Ascospores 



Diagram XIV. 



Thus the gametangia which copulate without further differentiation 

 arise on a hermaphrodite mycelium. The zygote develops to an ascus 

 in which 4 to 8 ascospores are formed by meiosis. This life cycle is 

 essentially the same as Dipodascus, Basidiobolus, Entomophthora, etc. 



