Northern Prairie Wildlife Research Center
Scarlet Smartweed (Polygonum amphibium var.
- Family: Smartweed (Polygonaceae)
- Flowering: June-August.
- Field Marks: Scarlet smartweed has thick, 2-inch long
racemes of red or pinkish-red flowers, sheaths that lack
bristles, and leaves that are usually rounded at the base.
- Habitat: Marshes, around ponds and lakes.
- Habit: Perennial herb with rhizomes.
- Stems: Erect, branched or unbranched, smooth except
near base, up to 3 feet tall.
- Leaves: Alternate, simple, broadly lanceolate to
oblong, pointed or rounded at the tip, usually rounded at the
base, without teeth, smooth or slightly hairy, up to 8 inches
long, 1 3/4-4 inches broad, with a sheath not bearing bristles.
- Flowers: Several densely crowded into a raceme
usually at least 2 inches long; each flower red or pinkish-red,
about 1/4 inch long.
- Sepals: Usually 5, red or pinkish red, united at the
- Petals: 0.
- Stamens: Usually 8.
- Pistils: Ovary superior.
- Fruits: Achenes pale brown, not shiny, not
triangular, 1/10-1/8 inch long.
- Notes: Waterfowl eat the achenes of this plant. Some
botanists do not consider the scarlet smartweed to be distinct
from the water smartweed.
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