Trees, shrubs or lianas, rarely herbaceous climbers; monoecious, rarely dioecious or polygamous. Indumentum usually of solitary, simple hairs, sometimes also of two-branched hairs, stellate bundles of hairs, or scale hairs (then young parts, buds, and inflorescences viscid). Leaves spirally arranged, rarely opposite or whorled, simple, biternate, digitate or (bi)pinnate; true stipules usually absent, pseudo-stipules sometimes present. Leaflets alternate to opposite, symmetric to distinctly asymmetric, entire or dentate to serrate or crenate. Inflorescences axillary, often together pseudoterminal, terminal or ramiflorous, thyrsoid, with or without branches; bracts and bracteoles present. Flowers usually unisexual, rarely bisexual, actinomorphic or zygomorphic. Sepals 4 or 5, rarely more, free to almost totally connate, equal to distinctly unequal, and then the outer 1 or 2 much smaller than the inner three, herbaceous to petaloid, in bud imbricate, valvate or apert. Petals absent or 2-6, free, usually clawed, often with 1 or 2 scales or auricles (= inrolled margins), scales crested or not. Disc complete or interrupted, lobed or annular to semi-annular, rarely with appendages or an erect (tubular) rim. Stamens 5-10(-74), usually 8, nearly always inserted within the disc, often exserted in male flowers; filaments glabrous or hairy; anthers basifixed, opening introrsely or latero-introrsely lengthwise; in female flowers present as staminodes with non-opening anthers. Ovary superior, 1-3(-8)-celled, lobed or not; style usually apical, rarely inserted between the lobes, stigma entire with (1), 2 or 3 lines or grooves, or (1-), 2- or 3-lobed; in male flowers rudimentary. Ovules 1 or 2 per locule, ascending, anatropous, campylotropous or amphitropous. Fruits capsular or drupaceous, or consisting of 2 or 3 samaras, when capsular usually loculicidal, rarely septicidal or septifragal. Seeds globose to obovoid, sometimes compressed, often with an arillode or a sarcotesta; endosperm absent; embryo usually thick, straight, sometimes sigmoid or convolute, cotyledons above each other (notorrhizal embryo) to laterally besides each other (lomatorrhizal embryo).
Distribution â 140 genera with c. 1350 species, widespread in tropical and subtropical regions of the world, especially well represented in South America. In Malesia 42 genera with ca. 235 species.
National Museum of Natural History, Netherlands
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