7 



PHYCOMYCETEAE: MUCORALES, 



ENTOMOPHTHORALES, ZOOPAGALES, 



ECCRINALES 



THE first three orders that form the subjects of this chapter agree in 

 the more or less coenocytic structure of the mycehum, in the union 

 of equal or unequal gametangia to form "zygospores," and in the total 

 absence of flagellate sexual or asexual cells. Also, chitin is present in most 

 of these forms and the cell walls do not show the cellulose reaction upon 

 the application of a solution of chloriodide of zinc. 

 These three orders may be distinguished as follows: 



Mucorales: mycelium very extensive, nonseptate or septate in older aerial 

 hyphae. Asexual reproduction typically by aplanospores formed in terminal 

 sporangia. In a few genera these are reduced to indehiscent sporangioles 

 which function as conidia. Sexual reproduction usually present. 



Entomophthorales : mycelium not very extensive, at first coenocytic but sooner 

 or later becoming septate and often falling apart into hyphal bodies. Asexual 

 reproduction typically by conidia which are usually shot off with violence. 

 Sexual reproduction frequently replaced by the parthenogenetic development 

 of "azygospores." 



Zoopagales: mycelia very slender, nonseptate or septate when older, attached 

 to their hosts (aquatic or soil-inhabiting amoebae, nematodes, or insect 

 larvae) by more or less complicated haustoria. Asexual reproduction by 

 various types of conidia. Sexual reproduction by the union of gametangia 

 to form zygospores of various shapes. 



In addition to the foregoing are the Eccrinales which form a group 

 of fungi whose relationship is very doubtful. They are placed here as a 

 sort of appendix to the Phycomyceteae so that they may not escape 

 attention. 



Order Mucorales. The Mucorales are widely distributed fungi with 

 a stout, well-developed, much branched coenocytic mycelium, very 

 similar to that of some representatives of the Saprolegniales. In the older 

 mycelium, especially in the aerial portions, septa may divide it into pluri- 

 nucleate segments, but the young mycelium and that submerged in the 



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