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Aquatic and Wetland Vascular Plants of the Northern Great Plains

15. Polygonaceae, the Smartweed Family

1. Polygonum L. -- Smartweed, knotweed, tear-thumb

2. Polygonum bicorne Raf.-- Pink smartweed

Very similar to P. pensylvanicum and often included in it by authors. Differing in having heterostylic flowers which are consistently pink; racemes appearing fringed due to the extruded stamens and styles, some flowers with the stamens exserted from the perianth and the styles included, others with the stamens included and the styles exserted; calyx 3-4 mm long, conspicuously exceeding the achene. Achenes lenticular, concave on both sides and usually with a slight elevation in the center of the concavity. Jul--Sep. Shores, stream banks, ditches and other wet, disturbed habitats; occasional in se SD, c and e NE; (IL to SD and e CO, s to LA, TX and into Mex.). P. longistylum Small.
GIF- Distribution Map

Map key

Previous Species -- Polygonum amphibium L. -- Water smartweed
Return to Family -- Polygonaceae - The Smartweed Family
Next Species -- Polygonum coccineum Muhl. ex Willd.-- Marsh smartweed

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