Stoutly taprooted perennial. Stems ascending to erect, glabrous, swollen at nodes, (10)-30-80 cm tall. Lvs glabrous or rarely hairy on surfaces, sometimes scabrid on margins, glaucous, ovate to linear-lanceolate to oblanceolate, acute, usually very shortly connate, 1.5-10 × 0.5-2 cm; lower lvs petiolate; upper lvs sessile. Infl. a lax 1-25-(40)-flowered dichasium; pedicels 5-15 mm; bracts ovate, green or scarious. Fls ☿. Calyx glabrous, glaucous, inflated, ovoid, 13-17 mm long; veins 20, weak with fine network of secondary veins; teeth broadly triangular, acute, ciliolate. Petals white; limb deeply emarginate, sometimes with 2 small lateral lobes near base; claw lobed near base of limb; coronal scales scale-like or oblong, 0-1 mm long. Styles 3, erect, c. 2 cm long. Capsule ovoid to spherical, included in calyx, dehiscing by 6 erect or recurved teeth; carpophore 2-3 mm long. Seeds dull brown, reniform, flattened, warty, 1-1.5 mm long.