BLASTOCLADIALES 653 



The most important contribution to our knowledge of this genus 

 has been Couch's (1945a) discovery of a Cystogenes type of life cycle 

 in Catenaria allomyeis Couch, entirely similar to that found in Allomyces 

 and Blastocladiella (see p. 625). 



Members of Catenaria occur on a wide variety of substrata. C. 

 anguillulae is outstanding among them in its ability to live as a sapro- 

 phyte in vegetable materials as well as a parasite of nematodes (this has 

 been confirmed by Couch, op. cit.). On the other hand, Couch reported 

 that C. allomyeis, which will parasitize all species of Allomyces, would 

 attack only Blastocladiella simplex, of the four species of that genus 

 tested, and would not infect Blastocladiopsis parva, Catenaria anguil- 

 lulae, Achlya caroliniana, or Saprolegnia parasitica. 



The resting spores of all the species have been observed. In Catenaria 

 anguillulae and C. allomyeis they he somewhat loosely in their container; 

 in C. sphaerocarpa, they completely fill it. Those of C. anguillulae seem 

 simply to be encysted sporangia with the contents somewhat contracted 

 and thick-walled. Karling (1938b) voiced a similar opinion regarding 

 the resting spores of C. sphaerocarpa. At germination, where this has 

 been seen, a tube is formed through which the swarmers emerge. 



KEY TO THE SPECIES OF CATENARIA 



Zoospores with numerous globules ; sporangia variable in shape 

 Parasitic in microscopic animals and their eggs and saprophytic in 

 vegetable debris; sporangia pyriform, subglobose, or irregular; 



with a Brachyallomyces type of life cycle C. anguillulae, p. 653 



Parasitic in Allomyces; sporangia and resting spores somewhat 



globose; with a Cystogenes type of life cycle C. allomyeis, p. 655 



Zoospores with a single conspicuous globule; sporangia predomi- 

 nantly globose C. sphaerocarpa, p. 657 



Catenaria anguillulae Sorokin 



Ann. Sci. Nat. Bot., VI, 4: 67, pi. 3, figs. 6-28. 1876 



(Fig. 44 G, p. 651) 



"Parasitic or saprophytic in nematodes, liver fluke eggs, and sapro- 

 phytic on cooked grass leaves, etc., and various kinds of nutrient agar. 

 Thallus composed at first of a branched or unbranched nonseptate or 



