A New Species of Pythium Isolated from Wheat Beneath Snow in Washington

SUMMARY

Pythium okanoganense differs from other members of the genus in having terminal oblate-spheroidal sporangia that infrequently proliferate internally to produce another sporangium within the old sporangial wall. Oogonia are smooth, except commonly a single, terminal hyphal protrusion extends from the oogonial wall. Antheridia are mostly single, frequently borne on inflated antheridial stalks, and monoclinous or less often diclinous. Oospores are aplerotic to nearly plerotic.