Observations on the Genus Catenaria

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Abstract
SUMMARY A fungus with a thallus similar to Catenaria Anguillulae and resting bodies that germinate as in Blastocladiella cystogena has been isolated from soil with its host, Allomyces anomalus. Growth experiments indicate that it is an obligate parasite on species of Allomyces and Blastocladiella simplex. It failed to grow on B. cystogena, B. laevisperma, or B. asperosperma, or on Blastocladia parva, Achlya sp. or Saprolegnia sp. Infection stages on Allomyces anomalus, the development of the thallus, zoosporangia, resting bodies, and the fusion of motile gametes are described. The fungus is named Catenaria Allomycis. Catenaria Anguillulae has been isolated from Texas soil and grown in pure culture on a variety of agars for the first time. It grows best on beef liver agar with or without sucrose, on which it forms a much branched thallus with numerous rhizoids. It can be transferred to liver fluke eggs, adult nematodes, and boiled grass leaves. Zoosporangia are formed in nearly all culture media tried. Resting bodies are formed sparingly in liver fluke eggs, nematodes, grass leaves, but are formed abundantly in strong concentrations of liver agar. The resting bodies are formed and germinate much as in Blastocladiella. On the bases of zoospore structure, method of discharge, and swimming and resting body structure and germination, the genus Catenaria is transferred from the Chytridiales to the order Blastocladiales, and Sparrow's subfamily Catenarioideae is raised to family rank. The species Catenaria Allomycis shows a parallel in its life history to Allomyces cystogenus while the life cycle of C. Anguillulae is similar to that of A. anomalus.