CHYTRIDIALES 331 



Phlyctochytrium closterii (Karling), comb. nov. 

 Rhizophydium closterii Karling, Amer. J. Bot., 33:333, figs. 25-28. 1946. 



"Thalli numerous, up to 18 on a host. Sporangia hyaline, smooth, 

 spherical (10-18 u.), or broadly pyriform (12-18 x 14-24 u.), with a 

 low broad exit papilla, up to 8 \x in diam. Zoospores spherical (2-2.5 u.), 

 with a minute refractive globule. Rhizoidal system fairly coarse, richly 

 branched and sometimes extending to the full length of the host cell, 

 usually inflated slightly at the base of the sporangium. Resting spores 

 spherical (10-16 \i), with a thick (2-2.5 \i), warty, light-brown wall and 

 coarsely granular content; functioning as prosporangia in germination" 

 (Karling, loc. cit.). 



Parasitic on Closterium sp., Karling (loc. cit.), Brazil; Closterium 

 sp., Sparrow (1952d: 763), United States. 



Sparrow observed only the zoosporangia. They conformed exactly 

 to those of Karling's species. The constancy of occurrence of the sub- 

 sporangial swelling in Sparrow's material and (from the figures) in 

 Karling's as well indicates that the species is better placed here in 

 Phlyctochytrium rather than in Rhizophidium. 



Phlyctochytrium laterale Sparrow 



J. Linn. Soc. London (Bot.), 50: 445, pi. 17, figs. 6-10. 1936 



Sporangium sessile, subspherical or domelike, 10-13 u. in height by 



12-15 (i. in diameter, wall smooth, thin, colorless; rhizoids branched 



or occasionally unbranched, arising from a main axis which emerges 



somewhat laterally from a subspherical subsporangial apophysis 6-7 ja 



Explanation of Figure 20 



A. Phlyctochytrium longicollum Sparrow, discharging sporangium on cysts 

 of Euglena sp. B. Phlyctochytrium papillatum Sparrow, discharging sporan- 

 gium on pine pollen. C. Blyttiomyces laevis Sparrow, discharging sporangium 

 on Zygnema sp. D-E. Dangeardia laevis Sparrow and Barr: D, resting spores 

 and a discharged sporangium seated on host cell, and immersed in gelatinous 

 sheath; E, sporangia, some of which are discharging zoospores. F. Rhizo- 

 phydium bullatum Sparrow, on pine pollen, two discharging sporangia and 

 a single resting spore. G. Blyttiomyces helicus Sparrow and Barr, on pine 

 pollen, sporangium with helically banded wall and large basal discharge pore. 



(A-C, F, Sparrow, 1952d; D-E, G, Sparrow and Barr, 1955) 



