LAGENIDIALES 993 



by a vesicle; cystospore 5-6 [jl in diameter; sexual reproduction not 

 observed. 

 Parasitic in eggs and embryos of rotifers, United States. 



Lagenidium pygmaeum Zopf 



Abhandl. Naturforsch. Gesell. Halle, 17: 96, pi. 1, figs. 29-31, pi. 2, figs. 1-12. 



1887 



Thallus tubular, contorted, with irregular lobulations, or spherical, 

 ovoid, ellipsoid, or reniform, frequently single, occasionally from two 

 to four in the host cell, forming a single sporangium provided with a 

 broad short somewhat irregular occasionally basally branched discharge 

 tube; zoospores broadly fusiform, 5 ■ 8 [i, laterally biflagellate, seg- 

 mented in the sporangium, completing their development in a vesicle 

 at the orifice; plants monoecious, rarely dioecious, gametangia resem- 

 bling the sporangia but somewhat stouter, formed by the septation of a 

 single thallus, occasionally a second septum delimiting a sporangium, 

 female gametangium strongly expanded, sometimes with papilla-like 

 outgrowths, male gametangium irregular, forming a fertilization tube; 

 resting spore spherical, lying loosely in the gametangium, 18-29 u, in 

 diameter, with a smooth double wall, contents with a large globule, 

 germination not observed. 



Parasitic in pollen grains of Pinus sylvestris, P. austriaca, P. laricio, 

 P. pallasiana, Zopf (he. cit.), Germany; coniferous pollen grains, 

 Maurizio (1895), de Wildeman (1895a: 74), Switzerland; pollen grains 

 of different plants, H. E. Petersen (1909:401; 1910: 537), Denmark; 

 (?) pollen, Voronichin (1920: 12), Russia; pollen of Pinus spp., Karling 

 (1941b: 108; 1941c: 357), Sparrow (1943:665), apple pollen, Karling 

 (1949a: 275), United States; pine-pollen bait, Sparrow (1952c: 106). 

 Cuba; from soil, pollen, Gaertner (1954b: 22), Egypt, South Africa. 



Schulz (1923: 181, figs. 4-7) reported this species from Danzig in 

 Cosmarium pyramidatum as well as in pine pollen. With the exception 

 of the organism in pine pollen (his Figure 7), those illustrated are hardly 

 identifiable with Lagenidium pygmaeum. 



Since the plants are predominantly monoecious and sex organs are 

 formed by the septation of a single thallus, the species is probably 



