ELATINACEAE (Waterwort Family)

Plants annual. Stems loosely ascending, often rooting at the lower nodes. Leaves opposite, sessile or nearly so, the blades simple, the margins entire or finely toothed. Stipules scalelike. Inflorescences axillary, the flowers solitary or in small clusters of 2 or 3. Flowers inconspicuous, actinomorphic, perfect, hypogynous, sessile or short-stalked. Sepals 2–5(6), free or fused toward the base. Petals 2–5(6), shorter than to about as long as the sepals, free. Stamens as many or twice as many as the petals, in 1 or 2 whorls, the filaments free, the anthers ovoid, attached at the midpoint, yellow. Staminodes absent. Pistil 1 per flower, of 2–5 fused carpels. Ovary superior, with 2–5 locules, the placentation axile or more or less basal. Styles 2–5, short, the stigmas capitate. Ovules numerous. Fruits capsules, 2–5-valved, thin-walled, the valves separating from the partitions at dehiscence. Seeds oblong to elliptic in outline, somewhat asymmetric at the ends, the surface with a network of fine ridges and/or pits, sometimes obscurely so. Two genera, 40–50 species, nearly worldwide.