CHYTRIDIALES 251 



very like those of R. closterii Karling; sporangia of the two, however, 

 are quite different. It is entirely possible that there are a number of 

 spherical multiporous sporangial types which differ only in the char- 

 acter of their resting spore. 



Rhizophydium racemosum Gaertner 

 Archiv f. Mikrobiologie, 21 : 125, fig. 7. 1954 



Sporangium at first spherical, later irregular in form and size, 10 by 

 10 fx, 18 by 14 u., 20 by 19 [x, 22 by 25 fx, with a conspicuous vacuole 

 and irregularly sized large oil drops, at maturity with rounded corners 

 at which the wall tears liberating the zoospores; rhizoidal system deli- 

 cate, barely visible, at first unbranched, then with short bushy branch- 

 es; zoospores, 2-2.5 jx in diameter, with a single droplet and 25 jjl 

 long flagellum, movement hopping; resting spores in clusters of up 

 to forty, adhering to one another, 7-8 [x at maturity. 



Pine pollen, Gaertner (be. cit.; 1954b); Egypt, Equatorial Africa. 

 South Africa. 



The species resembles Rhizophydium subcmgulosum but lacks papillae. 

 The resting stage is difficult to interpret. 



Rhizophydium coronum Hanson 

 Torreya, 44: 31. 1944 

 (Fig. 8, F-H, p. 97) 

 'Zoosporangia hyaline, spherical, ll-49(x in diameter, ovoid 10-48 x 

 14-54 [x, with laminated walls, outer lamina often disintegrating around 

 the upper half of the sporangium; one to five exit papillae, 3-3.7 x 

 9-11 \x. One to several concentric halos surrounding the developing 

 sporangia, reduced to one at maturity, which generally deliquesces 

 before spore discharge begins. Zoospores hyaline, spherical, 3.7-4.5 (x, 

 with one large refractive globule, 1.5 jx in diameter, the first zoospores 

 emerging as a coherent mass, separating after 6-14 minutes, the re- 

 mainder swimming in the sporangium and emerging singly. Rhizoids 

 fairly rigid, with 1.5-4.5 fx, thick walls, straight, coiled, sparingly or 

 richly branched, one rhizoid often predominant and very prolonged, 

 up to 500 [x in length. Resting spore spherical or sub-spherical, 22-35 ;x 



