CLADOCHYTRIACEAE 



11 



CLADOCHYTRIACEAE. This Small family contains species para- 

 sitic on algae, aquatic seed plants, and such economic plants as 

 corn, beets, and alfalfa. It is characterized by the possession of 



Fig. 20. Synchytriiim endobioticiim, causing potato wart. A. Young uni- 

 nucleate thallus with characteristic clear zone near periphery. B. The 

 thallus has segmented, each segment being multinucleate and each becom- 

 ing a sporangium. C. Sorus of mature sporangia, each of which has 

 rounded up. D. A pair of zoospores in preparation for fusion. E. Zygote 

 that has not yet settled down. F. Zygotes lodged on surface of pcKato in 

 preparation for penetration. G. Early stage in penetration. 



a rhizomycelium, which is typically limited to a single host cell. 

 In Physoderma zeae-maydis, causing brown-spot disease of corn 

 and teosinte, the rhizomvcehum becomes segmented and trans- 



