25h AQUATIC PHYCOMYCETES 



mucilage sheath surrounding the host, an unswollen stalk-like region 

 within the mucilage, and a branched rhizoidal system inside the host 

 cell. 



"Sporangium spherical (5-11 u.) containing 8 to 50 zoospores. At 

 maturity the entire sporangium wall deliquescing and the zoospores 

 when fully delimited swim away. Zoospores spherical (3 [x), unigut- 

 tulate, posteriorly uniflagellate. 



"Resting spores spherical (5-7 u.), wall smooth, containing one or 

 two large oil globules ; formed after fusion of a small male cell with 

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

 spore. Germination unknown" (Canter, be. cit.). 



Parasitic on the planktonic alga Sphaerocystis schroeteri, Canter 

 (loc. cit.), Dictyosphaerium pulchellum, Canter (1953:285), Great 

 Britain. 



Said by Canter (1951:144) to resemble Rhizophydium fulgens in 

 habit. 



This curious species resembles Nowakowskia hormothece (p. 448) 

 and Solutoparies pythii (p. 427) in the complete dissolution of the 

 sporangium wall. Unlike them, however, the protoplasmic mass under- 

 goes the greater part, if not all, of its cleavage into zoospores free in 

 the water. Further studies may indicate that this is a generically dis- 

 tinct form. 



Rhizophydium difficile Canter 



Trans. Brit. Mycol. Soc, 37 :119, figs. 4-5, pi. 3, fig. 4. 1954 



(Fig. 10 D-E, p. 108) 



"Thallus monocentric, eucarpic, consisting of an epibiotic spherical 

 sporangium formed by enlargement of the zoospore and a complicated 

 branched endobiotic rhizoidal system of limited extent. Sporangium 

 (12-20 [j. in diameter) containing up to ninety zoospores. Entire wall 

 of sporangium dissolves on dehiscence. Zoospore spherical 2.5 u. in 

 diameter, with a large posterior globule (1-1.35 [x), and a flagellum 

 12 u. long; movement smooth gliding. Resting spore spherical (8-13.6 [jl 

 in diameter) formed after fusion of a small male with a larger female 

 cell. Male directly adherent to wall of female. Wall thick, smooth, 



