Fl. N. Amer. 1: 231. 1838.
Herbs or subshrubs, perennial, 0.5–1 m, usually little-branched from base. Stems erect, puberulent to glabrate. Leaves: stipules free from petiole, 1-veined, subulate, 5–8 mm, subequal to petiole; petiole 2–9 mm, much shorter than blade, minutely puberulent to glabrate; blade narrowly linear to narrowly elliptic, 2–8 cm, 4–20 times longer than wide, base truncate, margins dentate to base, apex acute, surfaces minutely hairy abaxially, glabrous adaxially. Inflorescences axillary solitary flowers, scattered along stem, little, if at all, apically congested. Pedicels slender, 0.5–4 cm, longer than calyx. Flowers: calyx ribbed, 6–9 mm, basally hairy, lobes ovate; petals yellow-orange, 12–15 mm; staminal column sparsely and minutely hairy; style 8–11-branched. Schizocarps oblate, 6–8 mm diam., sparsely hairy apically, otherwise glabrous; mericarps 8–11, 3 mm, laterally reticulate, apex blunt to spinose, spines 0.2–1 mm.
Ala., Ark., Fla., Ga., La., Miss., Mo., N.C., S.C., Tenn., Tex., Va., s, e Mexico, Central America (Guatemala).
Varieties 2 (2 in the flora).