Northern Prairie Wildlife Research Center
Western Wetland Flora
Field Office Guide to Plant Species
Polygonum lapathifolium L.
- Family: Smartweed (Polygonaceae)
- Flowering: July-October
- Field Marks: The racemes of flowers usually drooping, and the sheaths on the stem of the plant are without bristles. The flowers are not bright pink.
- Habitat: Moist soil, wet meadows, roadside ditches, often in disturbed areas.
- Habit: Erect annual from a taproot.
- Stems: Upright, sometimes rather stout, up to 4 feet tall, smooth, the sheaths not bearing bristles at the tip.
- Leaves: Alternate, simple, narrowly to broadly lanceolate, up to 8 inches long, up to 1 1/2 inches wide, pointed at the tip, tapering to the base, usually smooth, often with glandular dots on the lower surface.
- Flowers: Many in few to several drooping racemes, the racemes up to 3 inches long, up to 1/2 inch broad, their stalks sometimes with stalked glands.
- Sepals: 6, partly united, white, greenish, or pale-pink, petal-like, 3-veined.
- Petals: 0.
- Stamens: Usually 9.
- Pistils: Ovary superior; styles 2, free to the base.
- Fruits: Achenes lenticular, shiny, 1/8-1/6 inch long.
- Notes: The achenes are eaten by waterfowl.
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