Stems are unbranched, thick, without hairs, ridged, sometimes reddish.
Lower rosette leaves are petioled, without hairs, alternately arranged on the stem, green with wavy margins. Stem leaves are arranged alternately along the stem, have a membranous sheath that encircles the stem and become progressively smaller nearer the tip.
Flowers in clusters on the upper portion of the stem, greenish sepals that become reddish-brown with age.
Fruit is a triangular, glossy, and brown to reddish-brown achene. A papery 3-valved or 3-winged structure surrounds the achene.
Curled dock Rumex crispus can be distinguished from other Rumex species by the shape of its fruit. Swamp dock Rumex brownii has spiked or toothed fruit and the fruit of sorrel Rumex acetosella have no obvious projections, while curled dock Rumex crispus has winged fruit.
Photo: Robert Whyte