250 AQUATIC PHYCOMYCETES 



Sparrow (1932b: 275, fig. 2d; 1952d: 762), United States; Typha 

 pollen, Sparrow (1936a: 441, pi. 17, fig. 16), Great Britain; fern 

 spores and pollen grains, Karling (1946c: 334, figs. 31-32), Brazil; 

 pine-pollen bait, soil, Sparrow (1952a: 36), Cuba; pine pollen, Gaertner 

 (1954b: 21), Egypt, Northwest Africa, West Africa, Equatorial 

 East Africa, South Africa; Gaertner (op. cit., p. 40), Sweden. 



Rhizophydium sphaerotheca differs from R. pollinis-pini primarily in 

 the number and position of the pores (there is only a single terminal 

 one in the latter). As understood here, R. sphaerotheca includes all 

 "Rhizophydium globosum" forms with multiporous, spherical, or sub- 

 spherical sporangia and a branched rhizoidal system which inhabit 

 the submerged microspores or microgametophytes of pteridophytes 

 and spermatophytes. Certain of the plants considered R. pollinis-pini 

 by Zopf (Joe. cit.) and some later investigators fall within these limits. 



The zoospores in the multiporous forms called R. pollinis-pini by 

 Zopf varied from 4 u, to 6 u. in diameter, and the sporangia in some 

 instances attained a diameter of 36 \x. 



Rhizophydium bullatum Sparrow 



Mycologia, 44: 762, fig. 1 h-i. 1952 

 (Fig. 20 F, p. 330) 



Sporangia sessile, in groups, spherical, with a smooth, double-con- 

 toured wall, varying from 6.6-15.4 u, in diameter; rhizoidal system 

 very delicate, much branched; zoospores numerous, spherical, 3 u. in 

 diameter, with a single basal colorless globule and long posterior 

 rlagellum; escaping through two to five sessile pores; resting spores 

 spherical, 6.6-11 u. in diameter, sessile, occurring in groups or oc- 

 casionally singly, with a thickened brownish wall beset with coarse 

 bullations; contents bearing a single large globule; germination not 

 observed. 



Parasitic on pine-pollen bait. United States. 



In the shape and size of its sporangia Rhizophydium bullatum re- 

 sembles R. sphaerotheca Zopf. No resting spores have ever been def- 

 initely associated with Zopf's species, but in Sparrow's they were 

 abundantly and quickly formed. The resting spores of R. bullatum are 



