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Western Wetland Flora

Field Office Guide to Plant Species

Willow-weed
Polygonum lapathifolium L.

JPG -- Species Photo JPG -- Distribution Map

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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Return to Species List -- Group 8
Next Species -- Lady's Thumb (Polygonum persicaria)

U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/plants/florawe/species/8/polylapa.htm
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Page Last Modified: Saturday, 02-Feb-2013 06:28:20 EST
Reston, VA [vaww55]