Description from Flora of China
Herbs, shrubs, trees, or sometimes spiny vines. Leaves opposite, alternate, or ± whorled; stipules absent; petiole usually present, well defined; leaf blade simple, herbaceous or slightly fleshy, margin entire. Inflorescences mostly terminal, less often axillary, of cymes, umbels, or verticils, sometimes 1-flowered or fasciculate, often grouped into panicles; bracts often inconspicuous, sometimes forming calyxlike involucre, or large and brightly colored. Flowers bisexual, rarely unisexual or polygamous, actinomorphic. Perianth constricted beyond the ovary, base persistent, closely enclosing ovary which appears inferior, limb petaloid beyond constriction, tubular, funnelform, or campanulate, apex 5-10-lobed, lobes plicate or valvate in bud, persistent or caducous. Disk absent. Stamens (1-)3-5(-many), hypogynous, free or connate at base, involute in bud; anthers 2-loculed, dehiscence longitudinal. Ovary superior, 1-loculed; ovule 1. Style 1; stigma globose. Fruit an achenelike anthocarp enclosed by persistent perianth, ribbed or winged, often glandular. Seed 1; endosperm present; embryo straight or curved.
About 30 genera and 300 species: tropics and subtropics, mainly in tropical America; six genera (two introduced) and 13 species (one endemic, three introduced) in China.
(Authors: Lu Dequan (鲁德全) ; Michael G. Gilbert)
Lu Dequan. 1996. Nyctaginaceae. In: Tang Changlin, ed., Fl. Reipubl. Popularis Sin. 26: 1–14.