Aphanomyces scaber

Aphanomyces scaber De Bary, Jahrb. Wiss. Bot. 2: 178. 1859
Hyphae delicate, branching, about 5-7.5 ^ thick, rarely as small as 2.5 /*; sporangia like the hyphae, of indefinite length; spores on encysting about 9.5 ju thick, narrow and elongate in the sporangium; oogonia terminal on short or moderately long branches, very small, 15-23.7 y. in diameter (averaging about 21.5 p in No. 1 of January 6, 1914), the surface uneven or varying to tuberculate, but the projections never so prominent as in A. stellatus, the wall thin, not pitted; eggs single, 13-18.5 (i in diameter (averaging about 15.5 p in No. 1 of January 6, 1914, about 13.3 & in No. 8 of November 15, 1913), eccentric, a single large oil-drop near one side, the protoplasm small in quantity and light in color, the wall rather thick; antheridia (not seen in our form) present on most of the oogonia, according to Fischer; not on all oogonia, according to Humphrey.
Type locality: Germany. Habitat: Fresh water and soil.
Distribution: Massachusetts, New York, and North Carolina; also in Europe