A perennial with an unbranched stem arising from basal leaves, with a single flowerhead. Disk flowers with spiny bracts. Ray flowers drooping, yellow, 1½–3½ inches long, notched at the tips. Basal leaves in a clump, strap-shaped, up to 8 inches long including stalks. Stem leaves shorter and lacking stalks. Fruits in a burrlike, dome-shaped head, blackening on drying.
Similar species: Our other coneflowers all have ray flowers that are pink or purplish pink. This is the only one with yellow ray flowers; this curious trait explains the species name, paradoxa. This species apparently sometimes hybridizes with other coneflowers. Hybrids usually have mottled or variegated ray corollas that can be a mix of pink and purple or may be orangish. Look for these in sites where yellow coneflower grows nearby the other species.