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.