CHYTRIDIALES 271 



Sporangium sessile, spherical, 20-25 \x in diameter, with a slightly 

 protruding apical papilla, wall fairly thick, with a faint reddish shim- 

 mer, contents colorless, with from one to two globules; zoospores 

 about 2.5 \x in diameter, with a colorless oil droplet, discharged through 

 an apical pore. 



On pine pollen, Schroeter (?), Germany. 



Serbinow (1907: 156) asserted that a facultative parasite of pollen 

 observed by him in Russia has sporangia which agree with Zopf's 

 Rhizophydium pollinis-pini, but which, in contrast to it, have an un- 

 branched rhizoid. Since Zopf had both true R. pollinis-pini and what 

 is called here R. sphaerotheca and since Serbinow did not further 

 describe the sporangia of his organism, it is impossible to say what 

 the latter observer had. It is evident, however, from Serbinow's em- 

 phatic statement, that a Phlyctidium species does occur on pollen. 

 Schroeter's specific description is included here since it appears to 

 be based, for the most part, on Braun's Rhizophydium pollinis-pini. 

 Because of Sorokin's previous application of Phlyctidium to Braun's 

 fungus, Schroeter's combination cannot be used. A new name will be 

 needed if Serbinow's observations are confirmed. 



Rhizophydium sciadii (Zopf) Fischer 

 Rabenhorst. Kryptogamenfl., 1 (4): 94. 1892 

 (Fig. 17 K, p. 228) 

 Rhizophyton sciadii Zopf, Abhandl. Naturforsch. Gesell. Halle, 17:91 



pi. 2, figs. 23-32. 1887. 

 Sporangium sessile, at first spherical or somewhat flattened at the 

 base, at maturity pyriform, with a broad blunt apex (the papilla), 

 up to 20 (jl high by 17 \x in diameter, walls smooth, colorless, slightly 

 thickened; rhizoidal system extensive, arising from one or two main 

 axes, richly branched; zoospores as many as eighty to one hundred 

 in the larger sporangia, spherical or ellipsoidal, 2.3-4 [x in greatest 

 diameter, with a relatively large (1-1.3 [jl in diameter) refractive, slightly 

 eccentric, colorless globule and a very delicate flagellum, emerging 

 upon the deliquescence of the thin-walled blunt apex of the sporangium ; 

 esting spore not observed. 



