CHYTRIDIALES 



63 



CHYTRIDIALES 



The Chytridiales, commonly called chytrids, include parasitic 

 and saprophytic fungi that are mainly aquatic. They occur on 



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Fig. 15. Stages in the development of Olpidiopsis. A. Biciliate zoospores. 

 B. Encysted stage that has settled upon a filament of Aphanomyces. C. 

 Migration of protoplast from cyst into filament of Aphanomyces. D. 

 Swollen tip of host hypha containing several zoosporangia, two of which 

 have formed exit tubes for escape of zoospores. E. Mature oospore of 

 O. luxiirians with two empty antheridia attached. (After Barrett.) 



fresh water algae, other aquatic fungi, microscopic animals, and 

 decaying tissues of seed plants. Some few marine species have 

 been described. A few are important pathogens on seed plants. 

 The feature of primary importance in the order is the produc- 



