Aphanomyces laevis

Aphanomyces laevis De Bary, Jahrb. Wiss. Bot. 2: 179. 1859
Hyphae slender, much branched, about 5-7.5 x thick; sporangia long and of same size as the hyphae, often extending to the substratum; spores 7.3-11 m in diameter after emerging, usually about 9-10 m, rod-shaped in the sporangium; oogonia terminal on short lateral branches, globular or nearly so, with smooth thin walls without pits, 18-33 /x in diameter; eggs mostly about 19-22 fx, thick-walled, eccentric; antheridial branches very abundant, sometimes twining around the oogonial branches in a knot, androgynous or diclinous; antheridia large, abundant on all oogonia and extensively wrapping about them; antheridial tubes developed and plainly visible.
Type locality: Germany.
Habitat: Fresh water and soil and parasitic on beets and algae. Distribution: Massachusetts, Michigan, and North Carolina; also in Europe.