Herbs, annual or short-lived perennial, cespitose, yellowish green to medium or dark olive green when dry, to 3.6 dm, not glaucous. Stems branched or rarely simple, with 1-2(-3) nodes, 0.7-2 mm wide, glabrous, margins usually entire, similar in color and texture to stem body; first internode 2-10 cm, usually shorter than leaves; distalmost node with 1-2 branches. Leaf blades glabrous, bases not persistent in fibrous tufts. Inflorescences borne singly; spathes green, obviously wider than supporting branch, glabrous, keels usually entire; outer 13-32.2 mm, 2-8.2 mm longer than inner, tapering evenly towards apex or occasionally slightly constricted proximal to apex, margins basally connate 2.3-6.7 mm; inner with keel evenly curved to straight, hyaline margins 0.2-0.3 mm wide, apex acute, occasionally erose, ending 0.3-4.6 mm proximal to green apex. Flowers: perianth flaring distally, campanulate basally; tepals maroon or pink to lavender-rose with purple stripes, or yellow with rosy purple bases; outer tepals 5-11 mm, apex acute, rarely aristate; filaments connate basally, occasionally to 1/2 their length, basally inflated and stipitate-glandular 0.5-0.8 mm; ovary similar in color to foliage. Capsules tan with purplish sutures and sometimes apex, ± globose, 2.1-4.2 mm; pedicel spreading to recurved. Seeds ± globose, sometimes with slight depression, 0.5-1 mm, rugulose. 2n = 32.

Flowering spring--fall. Roadsides, old fields, and other disturbed areas, stream banks, wet areas bordering woods; 0--80 m; Ala., Ark., Fla., Ga., La., Miss., N.C., S.C., Tex.

Sisyrinchium rosulatum is apparently weedy throughout much of its range.