254 AQUATIC PHYCOMYCETES 



Saprophytic on chitin, Antikajian (be. cit.)., chitin bait, from moist 

 soil, Karling (1948c: 508), United States. 



The fungus is said to be limited to chitinous substrata. 



Rhizophydium constantineani Saccardo 



Sylloge fungorum, 17: 512. 1905 



(Fig. 17 F, p. 228) 



Rhizophydium vaucheriae Constantineanu, Revue Gen. Bot., 13:380, 

 fig. 81. 1901. Non Rhizophydium vaucheriae de Wildeman, Mem. Herb. 

 Boissier, 1900 (15): 6. 



Sporangium sessile, spherical or subspherical, 6-8 \x in diameter, 

 wall smooth, colorless; rhizoidal system very delicate, consisting of a 

 few short branches which arise from a main axis ; zoospores from four 

 to six, spherical, 3.5 \x in diameter, with a colorless, eccentric globule, 

 escaping through a small apical pore and forming a temporary group 

 attached to the pore by the tips of the flagella ; resting spore not observed. 



On filaments of Vaucheria sp., Saccardo (loc. cit.), Rumania; Oedo- 

 gonium sp., Cosmarium sp., Richards (1956: 261, pi. 6, figs. 1-2), Great 

 Britain. 



The species has been discussed by Minden (1915:326) under Rhi- 

 zophydium sphaerocarpum (Zopf) Fischer. From the smaller size of 

 its sporangia, however, and the branched nature of the rhizoids, it 

 cannot without further study be referred to Zopf's fungus. 



Rhizophydium planktonicum Canter x 

 Canter and Lund, New Phytologist, 47: 259, figs. 10-1 1. 1948 

 (Fig. 10 H-I, p. 108) 

 "Thallus epibiotic sessile or stalked, sporangium spherical, 4.5-9.3 y. 

 in diameter, with 4-1 5 zoospores. Zoospores spherical 3-3.7 \x in diam- 

 eter, uniguttulate, posteriorly uniflagellate, emerging in a mass on 

 gelatinization of the apex of the sporangium wall. Intramatrical rhi- 

 zoid unbranched or once branched, not tapering. Resting spores spher- 

 ical 4-7 [x in diameter, wall smooth, the content with numerous small 

 oil globules; arising from fusion of the contents of a small male with 

 a larger female cell, the former remaining as an appendage to 



1 See also Paterson (Mycologia, 50:93. 1958). 



