Stems procumbent to erect, 3–15 cm. Leaf blades ovate to lance-linear, 10–60 × 4–31 mm. Phyllaries 13–21, unequal. Ray corollas 2–9 mm. Cypselae: rays 2.5–3.5 mm with awns 1–3 mm, clearly 3-faced, adaxial faces often 2–3-nerved; discs strongly dimorphic within single heads: outer 4-angled, wingless, inner ± flattened, 1–2-winged. 2n = 16, 32.

Flowering summer–fall. Ruderal; 10–1000 m; introduced; Calif., Md., Tex.; Mexico; Central America.

Sanvitalia procumbens has been seen only sporadically in the flora; it probably is not a resident.