Northern Prairie Wildlife Research Center
Western Wetland Flora
Field Office Guide to Plant Species
Polygonum punctatum Elliott
- Family: Smartweed (Polygonaceae)
- Flowering: July-October
- Field Marks: This species is readily distinguished by the black dots on the white sepals and the bristly sheaths on the stem.
- Habitat: Wet soil, wet meadows, marshes, roadside ditches, around lakes and ponds.
- Habit: Erect perennial, but with the lower branches sometimes rooting at the nodes, usually bearing rhizomes and stolons.
- Stems: Upright, usually rather slender, up to 3 feet tall, but usually shorter, usually smooth, the sheath bearing bristles at the top.
- Leaves: Alternate, simple, elliptic to lanceolate, up to 4 inches long, up to 3/4 inch wide, pointed at the tip, tapering to the base, usually smooth, or occasionally strigose on the lower surface.
- Flowers: Many in arching or erect, interrupted racemes, the racemes up to 4 inches long, about 1/4 inch broad.
- Sepals: 6, partly united, white to greenish white, petal-like, the surface covered with black dots.
- Petals: 0.
- Stamens: Usually 9.
- Pistils: Ovary superior; styles 2 or 3.
- Fruits: Achenes black, shiny, lenticular to 3-angled.
- Notes: The achenes are eaten by waterfowl.
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