Annual, scapigerous, palustrine
herbs, juice milky. Leaves radical, elliptic, entire, acute. Inflorescence
umbellate, with flowers on a scape, scape longer than leaves. Flowers bisexual,
bracteate. Sepals 3, herbaceous, persistent. Petals 3, white, longer than
sepals, deciduous. Stamens usually 9, or 8-12, 6 outer in pairs, opposite to
the sepals, 3 inner stamens opposite to the petals, anthers oblong. Carpels
6-9, whorled on a flat receptacle, 1-celled, placentation parietal. Fruits of
6-7 follicles. Seeds numerous.