Herbs , annual, caulescent, glabrous or glabrate, from fibrous roots. Stems leafy, mostly at base, erect to decumbent, simple or branching. Leaves: basal rosulate, winged-petiolate; cauline opposite or whorled, subsessile or sessile; blades unlobed. Inflorescences axillary or terminal, 1-flowered; bracts absent; bud globose, nodding. Flowers: receptacle sometimes expanded into small ring beneath calyx; sepals 3, with overlapping, loosely connivent flaps; petals 6; stamens 4-6 in 1 series or ca. 12 in 2 series; filaments usually dilated distally; pistil 3-carpellate; ovary 1-locular, linear-oblong; stigmas 3. Capsules erect, linear, greatly elongate at maturity and often spirally twisted, dehiscing apically by separation of valvelike carpels. Seeds few, black, shiny, aril absent. x = 8.