|Abstract||Trees, shrubs, herbs, or armed climbers; roots not rarely tuberous. Indument consisting of simple hairs. Leaves simple, exstipulate, opposite or rarely in whorls or pseudowhorls, sometimes unequal in one pair. Inflorescence cymose, often thyrsoid, corymbose or umbellate terminal or axillary, sometimes cauliflorous. Bracts and bracteoles present, sometimes very small, not rarely early caducous. Flowers actinomorphic, bisexual or unisexual by reduction; pedicelled, with 1-3 bracteoles sometimes coloured, or sustained by an involucre. Perianth tubular, campanulate, funnel-shaped, or urceolate, sometimes articulated with the pedicel; the basal part persistent, enclosing the receptacle, tubular, club- or funnel-shaped, often accrescent; the apical, mostly circumscissile caducous part plicate or valvate in bud, with (4—)5—10 lobes, green or coloured. Stamens 1-40, rarely more, in 1-2 whorls, connate at the base, free from the perianth; anthers 2-locular, latrorse, basifixed. Ovary (sub)sessile, superior, 1-celled, with one erect, anatropous ovule. Style terminal, stigma capitate or fimbriate- to shortly lobed. Basal persistent part of the perianth accrescent in fruit and enveloping the fruit, the whole being known as anthocarp; anthocarp indehiscent, smooth, or with viscid ribs and glands, sometimes the glands accrescent into prickles; pericarp thin. Seed 1; embryo straight or folded; endosperm mealy or reduced to a gelatinous rest.|
Distribution. About 26 genera with 300 spp. in the New World, particularly in South America, with poor representations of mostly widespread (native or introduced) species in the warm parts of the Old World. Although the family is predominantly tropical, its area reaches to 38° SL in New Zealand and to 45° SL in Argentina. In Malesia there are 19 spp. in 4 genera, of which only Pisonia is undoubtedly native.