Coreopsis hamiltonii (Elmer) H.Sharsm.

Annuals, (3–)10–20+ cm. Leaf lobes oblong to linear, 1–8(–15) × 0.5–1 mm. Peduncles 3–9(–18) cm. Calyculi of 3–5 oblong to linear bractlets 1–3(–5) mm. Phyllaries 8, ± lance-ovate, 4–8 mm. Ray florets 8; laminae 3.5–8 mm. Disc florets ca. 40; corollas 2.5–3.5 mm. Paleae seldom basally adnate to and falling with disc cypselae. Ray cypselae narrowly obovate, 5–6 mm. Disc cypselae narrowly oblanceolate, 4–5 mm; pappi ca. 1 mm. 2n = 24.