Britton, N.L., and A. Brown. 1913
Herbs, annual. Taproots stout. Stems simple proximally, branched distally, terete. Leaves opposite, somewhat clasping or connate proximally into sheath, petiolate (basal) or sessile (cauline); blade 1-veined, lanceolate to oblong- or ovate-lanceolate, apex acute to obtuse. Inflorescences terminal, lax to erect, open, often flat-topped cymes; bracts paired, foliaceous; involucel bracteoles absent. Pedicels erect. Flowers: sepals connate proximally into tube, 9-17 cm, tube whitish green, 5-veined, cylindric to ovoid, 5-angled or winged, especially in fruit, commissures between sepals absent; lobes green, 1-veined, obovate to broadly triangular, shorter than tube, margins green or reddish, scarious, apex acute or acuminate; petals 5, pink to purplish, clawed, auricles absent, coronal appendages absent, blade apex entire or sometimes briefly 2-fid; nectaries at filament bases; stamens 10, adnate to petals; filaments distinct; staminodes absent; ovary 1-locular or sometimes 2-locular proximally; styles 2(-3), filiform, 10-12 mm, glabrous proximally; stigmas 2(-3), linear along adaxial surface of styles, papillate (30×). Capsules oblong to subglobose, exocarp opening by 4(-6) slightly spreading teeth, endocarp opening irregularly; carpophore present. Seeds ca. 10, black, subglobose, laterally compressed, papillose, marginal wing absent, appendage absent; embryo peripheral, curved. x = 15.