Northeast Wetland Flora
Field Office Guide to Plant Species
Potamogeton amplifolius Tuckerman
- Family: Pondweed (Potamogetonaceae)
- Flowering: July-September
- Field Marks: This pondweed is characterized by its broad submersed leaves up to 3 1/2 inches wide, its fruiting spikes 1/2-3/4 inch thick, and its prominent beaks on the achenes.
- Habitat: Lakes, streams.
- Habit: Perennial aquatic herb from whitened or reddish rhizomes.
- Stems: Branched or unbranched, smooth, not as large in diameter as the rhizomes.
- Leaves: Of three kinds: floating leaves ovate to elliptic, rounded but sometimes with a short point at the tip, tapering or rounded at the base, leathery, up to 4 inches long, up to 2 inches wide, on a stalk up to 8 inches long; submersed leaves on lower part of stem lanceolate, rounded or somewhat pointed at the tip, up to 8 inches long, up to 3 inches wide; submersed leaves on upper part of stem broadly lanceolate to ovate, rounded or somewhat pointed at the tip, up to 8 inches long, up to 3 inches wide.
- Flowers: Crowded into axillary spikes, the spikes up to 3 inches long, 1/2-3/4 inch thick; flowers sessile.
- Sepals: 4, free from each other, green, nearly spherical, up to 1/6 inch across.
- Petals: 0.
- Stamens: 4.
- Pistils: 4, free from each other, smooth.
- Fruits: Achenes obovoid, rounded and usually prominently keeled on the back, up to 1/4 inch long, with a prominent beak about 1/20 inch long.
- Notes: The achenes are eaten by waterfowl.
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