CHYTRIDIALES 361 



PODOCHYTRIUM CLAVATUM Pfitzer 



Sitzungsber. Niederrhein. Gesell. Natur- und Heilkunde, 1869: 62. 1870 



(Fig. 21 L, p. 360) 



Septocarpus corynephoms Zopf, Nova Acta Acad. Leop.-Carol., 52: 348, 

 pi. 20, figs. 21-28. 1888. 



Sporangium sessile, occasionally borne on a short needle-like portion 

 of the penetration tube, clavate or obpyriform, wall smooth, often stout, 

 colorless, not giving a cellulose reaction, 8-19.2 \x high by 5-8.4 \l in 

 diameter, resting directly on a knoblike sterile basal cell, 2.5-3 \l in 

 diameter; rhizoids extremely delicate, branched, arising from the tip of 

 a sometimes prolonged penetration tube; zoospores spherical, 3 u, in 

 diameter, with a single colorless slightly eccentric globule, sometimes 

 moving within the sporangium, emerging upon the dissolution of a 

 broad scarcely visible apical papilla and either forming a temporary 

 motionless mass at the orifice or swimming directly away; resting spore 

 not observed (?). 



Parasitic on Pinnularia, Pfitzer (loc. cit.), Zopf {loc. cit), Germany; 

 various diatoms, de Wildeman (1890: 26), Belgium; Melosira, de 

 Wildeman (1894: 157), France; Pinnularia, Melosira varians, Am- 

 phora, Gomplwnema micropus (possibly resting spore of fungus), 

 Scherffel (1926a: 174, pi. 9, figs. 13-16), Hungary; Navieula spp., 

 Sparrow (1933c: 524, fig. I, 13), Pinnularia sp., Sparrow and Barr 

 (1955: 554), United States ;Fragilaria sp., Sparrow (1936a: 449, fig. 4 b, 

 g-h), Great Britain; Tabellaria flocculosa, Tokunaga (1934b: 391, pi. 

 11, figs. 11-12), Japan. 



Scherffel has described an epibiotic "stopper-like" resting spore, 

 6-8 \x long by 4-5 [jl thick, with rounded apex, smooth thickened wall, 

 and fatty contents as possibly belonging to this species. The resting 



chytrium clavatum Pfitzer on cell of Fragelaria. M-O. Scherffeliomyces para- 

 sitans Sparrow on Euglena: M, discharging sporangium resting on host cell; 

 N, mature sporangium with attached zoospore cyst; O, two epibiotic resting 

 spores with attached zoospore cysts. 



(A, Bartsch, 1939; B-E, K-O, Sparrow, 1936a; F-G, Serbinow, 1907; 

 H-J, Domjan, 1936) 



