990 AQUATIC PHYCOMYCETES 



Lagenidium oedogonii Scherffel 

 Hedwigia,41:(105). 1902; Arch. Protistenk., 52: 109, pi. 5, figs. 209-219. 1925 



(Fig. 80D-E, p. 987) 



Thallus irregularly saccate or ovoid, sometimes with broad finger-like 

 prominent lobes or short branches, occasionally tubular and simple or 

 coiled, variable in size, 20-25 by 35-52 u., infection tube and zoospore 

 case often persistent, forming a single sporangium with one, generally 

 short, discharge tube, which is slightly constricted when passing through 

 the host wall (rarely two discharge tubes); zoospores grape-seed-like, 

 6 \x long, furrowed, with a prominent bright spot (vacuole?), predomi- 

 nantly formed in a vesicle at the orifice of the discharge tube, capable of 

 repeated emergence, rarely assuming motility within the sporangium, 

 emerging individually and encysting at the orifice, cysts 4 u, in diameter, 

 escaping as secondary laterally biftagellate zoospores; plants dioecious, 

 female gametangium resembling the sporangium, male gametangium 

 smaller, often somewhat tubular; resting spore spherical, 12-14 \i in 

 diameter, lying loosely in the gametangium, with a smooth colorless 

 wall 2 [j. thick, contents with a parietal layer of coarse granules and a 

 large eccentric lustrous fat globule, germination not observed. 



Parasitic in Oedogonium sp., Scherffel (loc. cit.), Domjan (1936: 52, 

 pi. 1, figs. 170, 180-181), Berczi (1940: 86), Hungary; Oedogonium sp., 

 Couch (1935b: 386, figs. 22-31), Oedogonium sp., Sparrow (1943: 663), 

 United States; O. boscii, Rieth (1954: 164, fig. 1), Germany. 



The ^r/?/va-like behavior of the zoospores in rare instances might 

 perhaps be interpreted as repeated emergence or dicystism in the sense 

 of Coker and Matthews (1937: 15), but not as diplanetism (dimor- 

 phism). Emergence of the spores in Pythium-\ike fashion, followed by 

 repeated emergence has been noted by Couch (1935b: figs. 32-34) in 

 what may be a small form of this species. 



Scherffel points out that in sexual reproduction there is definite dis- 

 tinction between the male and the female gametangia, the former being 

 smaller and often more tubular than the latter (Fig. 80 E). This is of 

 particular interest since it appears to indicate that here degree of thallus 

 development is not correlated with degree of differentiation of the 

 sexual organs. However, further observations are needed on this phase 

 of the species. 



