Silphium trilobatum Linnaeus, Syst. Nat. ed. 10, 2: 1233. 1759 (as trilobatu); Wedelia trilobata (Linnaeus) Hitchcock

Leaf blades 5–18 × 1–5+ cm. Ray laminae 6–15 mm. Disc corollas 3.5–6 mm. Cypselae 3–5 mm. 2n = ca. 40, ca. 50–54, 50–58, 56, ca. 56, 57, and 60.

Flowering nearly year round. Ruderal, wet places; 0–10 m; introduced; Fla.; Mexico; West Indies; Bermuda; Central America; South America; probably introduced in Asia; Indian Ocean Islands; Pacific Islands; Australia.

Sphagneticola trilobata is probably native to subtropics and tropics of the New World and probably introduced in Old World. It is increasingly cultivated and is to be expected as escaped or persisting in warm to hot, sandy spots anywhere in the flora area. Report of it from Louisiana has not been confirmed.