Rumex cristatus is known from Missouri, Illinois, and Kansas; it may occur also in adjacent states
Plants perennial, glabrous or indistinctly papillose exclusively on veins of leaf blades abaxially, with fusiform, vertical rootstock. Stems erect, branched from above middle or in distal 2/3, 70–150(–200) cm. Leaves: ocrea deciduous or partially persistent at maturity; blade broadly lanceolate to oblong-lanceolate, normally 15–25(–35) × 5–7(–12) cm, base truncate, rounded, or slightly cordate, margins entire, undulate or weakly crisped, occasionally flat, apex acute or acuminate. Inflorescences terminal, occupying distal 1/2–2/3 of stem, normally dense or interrupted near base, broadly paniculate (branches of inflorescence mostly with 2d-order branches), branches usually straight or arcuate, rarely indistinctly flexuous. Pedicels articulated near middle, filiform, 6–14 mm, articulation distinctly swollen. Flowers 15–20 in whorls; inner tepals orbiculate, 6–8(–9) × 6–7.5(–8) mm, base usually distinctly cordate, margins entire or subentire near apex, distinctly dentate in basal 1/2, apex acute or subacute, teeth 0.5–1 mm; tubercles normally 3, rarely 1, distinctly unequal. Achenes dark brown or brown, 2.8–3.5 × 2–2.5 mm. 2n = 80.
This plant might be poisonous
How to get rid of:
Getting rid of curly dock by hand pulling is not a good idea. Any part of the root that is left in the soil will only produce new plants. You also cannot employ animals to graze on curly dock as a control because of the plant’s toxicity to livestock. The most successful methods of controlling curly dock are mowing it down regularly, where applicable, and the regular use of herbicides. Herbicides should be applied at least twice a year, in spring and fall. For best results, use herbicides containing Dicamba, Cimarron, Cimarron Max or Chaparral.