Polygonaceae
Smartweed Family
Polygonum pensylvanicum L. var. laevigatum Fern.
- Stem: annual; 2’ to 4’ tall; branching above; reddish, smooth, with swollen nodes.
- Leaves: alternate; oval, tapering to both ends; 3 1/2” by 3/4” to 4 1/2” by 1”; leaf stalks 1/4” to 1/2” long; sheaths surrounding the stems at the base of the leaf stalks 1/2” long, with smooth margins; appressed-hairy on the margins, otherwise smooth.
- Inflorescence: raceme; flowers closely packed; 1” to 2” long by 1/2” in diameter; 3/16” flower stalks stiff-hairy, from the stem tip and upper leaf axils.
- Flowers: sepals pink, 5/16” long, overlapping, the tip of the flower nearly closed; without petals; flowering from mid-July to mid-August.
- Fruits: seedlike, flat, circular, shiny black, 1/8” long, developing within the calyx; fruiting begins in early August; fruits begin dropping in September.
- Habitat: common in moist, recently disturbed soil; on moist prairies, on roadsides, in cultivated fields, and in other open places.
- Bibliography from Biodiversity Heritage Library
- Vascular Plants of Iowa
Can be found in these counties:
