Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Potamogeton epihydrus Raf.
- Family: Pondweed (Potamogetonaceae)
- Flowering: July-September
- Field Marks: The distinguishing characters of this species are the flattened stems, the submersed leaves 1/4-1/2 inch wide, and the tooth-like beak of the achene.
- Habitat: Lakes and streams.
- Habit: Aquatic perennial with slender, creeping rhizomes.
- Stems: Flattened, sparsely branched or unbranched, smooth.
- Leaves: Of 2 kinds: floating leaves usually opposite, stalked, elliptic to oblong-lanceolate, rounded or sometimes short-pointed at the tip, up to 3 1/2 inches long, up to 1 3/4 inches wide, leathery, with flattened stalks; submersed leaves linear-elongate, alternate, stalkless, and with a netted appearance along the midvein, up to 8 inches long, up to 1/2 inch wide.
- Flowers: Crowded into spikes, the spikes cylindrical, up to 2 inches long; flowers sessile.
- Sepals: 4, green, free from each other, about 1/6 inch long.
- Petals: 0.
- Stamens: 4.
- Pistils: 4, free from each other, smooth.
- Fruits: Achenes obovoid, flattened laterally, 3-keeled, about 1/5 inch long, with a tooth-like beak.
- Notes: The achenes are eaten by waterfowl.
Previous Species -- Water-thread Pondweed (Potamogeton diversifolius)
Return to Species List -- Group 4
Next Species -- Leafy Pondweed (Potamogeton foliosus)