1. Cotyledons are narrow and long, often deep purple to crimson.
2. First true leaves are broadly lanced shaped. Subsequent leaves have wavy margins.
3. Broad-leaved docks (R. obtusifolius) have broad lower leaves and bear thick clusters of brownish-green flowers on tough upright stems. Curled-leaved docks (R. crispus) have narrow lance-shaped leaves with very wavy margins and bear clusters of small greenish-red flowers.