PERONOSPORALES 1047 



doubtfully distinct from Pythiogeton transversum, the complex of 

 branched sporangiferous hyphae being the chief point of difference. The 

 sporangium, however, appears more narrowly bursiform than in typical 

 P. transversum. The sporangia in Sparrow's material were about 60 \i 

 long and tapered from 20 \l to 8 \± in diameter. The material studied by 

 Shen and Siang had hyphae 3-4 \x in diameter, the main axes up to 6.6 u.; 

 zoosporangia 28-65 \i long by 24-53 \x wide, with a discharge tube 

 16-62 fj. long by 4-6 u, in diameter. The cysts of the discharged zoospores 

 were 10-1 1 \x in diameter. No sex organs were seen. 



Pythiogeton transversum Minden 

 Falck, Mykolog. Untersuch. Berichte, 2(2): 242, pi. 7, figs. 66-72. 1916 



(Fig. 88 A-D, p. 1045) 



Mycelium composed of slender moderately branched hyphae; zoo- 

 sporangium usually intercalary, placed near the tip of the hypha, which 

 appears as a somewhat evanescent short appendage, irregularly bursi- 

 form, occasionally somewhat spherical, 70-299 [x long (without includ- 

 ing the discharge tube) by 42-79 y. in diameter, the long axis usually 

 nearly at right angles to that of the supporting hypha, to which it is 

 attached near the narrower end, discharge tube more or less prolonged; 

 zoospores reniform, laterally biflagellate ; oogonium terminal or inter- 

 calary, at maturity polygonal, 37-51 [x in diameter (averaging 50 (jl), 

 antheridium single, androgynous (monoclinous), frequently helically 

 involved by or involving the supporting hypha of the oogonium, inter- 

 calary, placed near the tip of the hypha, which appears as a somewhat 

 evanescent short appendage, applied near the base of the oogonium; 

 oospore spherical, nearly filling the oogonium, 33-50 u. in diameter, 

 with a thick refractive somewhat yellowish wall, contents bearing a 

 large oil globule, germination not observed. 



On various fruits and on stalks of water hemlock, Minden (he. cit.), 

 Germany. 



In the globose character of its sporangia a fungus referred to this 

 species by Sparrow (1933c: 533, pi. 49, fig. 24) more nearly resembles 

 Pythiogeton uniforme Lund. As may be seen, Minden considered the 



