Aquatic and Wetland Vascular Plants of the Northern Great Plains

Polygonaceae, The Smartweed Family

Annual and perennial herbs with small flowers often aggregated in conspicuous inflorescences. Leaves simple, alternate, the blades sometimes undulate-crisped along the margin, otherwise entire; stipules united to form a membranous or papery sheath (the ocrea) around the stem at each node. Flowers borne in spikelike racemes or in small axillary clusters (Polygonum), or in dense, terminal panicles of racemes in which the flowers are densely whorled on the branches (Rumex), in the latter case, the inflorescence often comprising much of the upper part of the plant. Flowers perfect (in those included here), regular; perianth consisting of a calyx only; in Polygonum the sepals petaloid or at least so on the margins, whitish to pink or sometimes yellowish, in a cycle of (4)5(6); in Rumex the sepals herbaceous, green to brown, in 2 cycles of 3, the 3 inner sepals accrescent, becoming broadly winged and appressed to each other, persisting to enclose the achene; stamens 4-8; pistil 1, 2- or 3-carpellary, styles 2-3, ovary superior, 1-celled. Fruit a trigonous or lenticular achene.

Lead	Characteristic	Go To
1	Flowers in spikelike racemes or in groups of 1-few in the axils of ordinary leaves, whitish to pink or greenish, the calyx petaloid at least on the margins	Genus Polygonum
1	Flowers in dense terminal panicles of racemes in which flowers are in dense whorls, green to brown, the calyx herbaceous	Genus Rumex