cuneata Sheld., duck potato, wapato, arrowhead
Sagittaria latifolia Willd., duck potato, wapato, arrowhead
Duck potato plants are shoreline perennials which usually have distinctly arrowhead shaped leaves. Both species have upright, emergent leaves and whorls of three petaled flowers on long stalks originating at the plant base. Large, round tubers are produced. S. cuneata grows to 0.5 m high and S. latifolia grows to 1.5 m high.
Leaf: S. cuneata: emergent arrowhead-shaped leaves, 5-15 cm long; may also have long, narrow, oval-to-heart-shaped floating leaves, and long, narrow submersed leaves. Stalks usually triangular in cross section. S. latifolia: variable leaf shapes, but usually has emergent 5-45 cm long arrowhead shaped leaves when mature. Leaf stalks usually angular in cross section.
Stem: Short, at plant base (stem-like leaf stalks arise from plant base) .
Flower: Usually in whorls of three, each with 3 white petals and 3 green sepals (1-2 cm long). S. cuneata: flowers to 2.5 cm across. When in fruit the stalks are held upright. S. latifolia: flowers to 4 cm across. When in fruit the stalks spread outwards.
Fruit: Achenes approximately 2 mm long, crowded on globe-shaped heads. S. cuneata: beak at achene tip < 0.5mm. S. latifolia: beak 1-2 mm, horizontal.
Root: Rhizomes with thick round white or bluish tubers that may grow as large as chicken eggs.
Propagation: Tubers, rhizomes, seeds.
Importance of plant: Tubers were an important food source for Native Americans. Tubers also provide food for beavers and muskrats. Tubers and achenes provide food for waterfowl.
Distribution: S. cuneata: Throughout the United States and southern Canada; only east of Cascades in Oregon and Washington. S. latifolia: Common on Pacific coast, central, and eastern United States; in Washington, primarily west of Cascades and the Columbia River Gorge.
Habitat: Shorelines and marshy areas up to 1.5 m deep.
May be confused with: Each other. Leaf and achene characteristics are used to distinguish them. Unlikely to be confused with other plants when the arrowhead shaped leaves are present, though some less common species of Sagittaria don't have this leaf shape. May be confused with water plantains (Alisma spp.), water celery (Valisneria sp.), or bur-reeds (Sparganium spp.) which all have ribbon-like underwater leaves.
Photographs: Sagittaria cuneata, Sagittaria latifolia
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