Lythrum alatum Pursh var. ovalifolium A. Gray, Boston J. Nat. Hist. 6: 187. 1850; L. alatum var. pumilum A. Gray

Herbs perennial, slender, 1.5–4dm, green to slightly gray glau­cous, glabrous. Stems from creeping rhizome, erect or decumbent, much-branched dis­­tally. Leaves mostly alternate; sessile or subsessile; blade (on main stem) oblong to suborbiculate, 15–25 × 6–15 mm, mostly longer than internodes and closely overlapping distally, (on branches) oblong to linear, 6–10 × 1–2 mm, base attenuate. Inflorescences racemes. Flowers alternate, subsessile, pedicel slender, distylous; floral tube without red spots, obconic, becoming cylin­drical, 3.5–6 × 1.3–3 mm; epicalyx segments 2 times length of sepals; petals pale purple to purple, sometimes with red mid­veins, obovate, 3–5.5 × 1.5–5.5 mm, about as long as floral tube; nectary encircling base of ovary, very narrow; stamens 6. Capsules septicidal or septi­fragal. Seeds ca. 25, obovoid to fusiform. 2n = 20.

Flowering spring–fall. Wet areas; 200–1500 m; Tex.

Lythrum ovalifolium is known only from the Edwards Plateau. It is part of a complex of species related to L. alatum (J. A. Morris 2007).