Herbs, subshrubs or shrubs, with erect or creeping stems, simple hairs often present. Leaves simple, entire, veins usually reticulate; stipules absent or vestigial. Inflorescence terminal or rarely axillary, a condensed raceme (head), rarely elongated, with or without involucral bracts. Flowers actinomorphic, unisexual or bisexual; sepals 4, on rim of long floral tube; corolla lobes absent or small, when present, scale-like and opposite sepals on rim of floral tube; stamens 2, 4, 8 or rarely 1, in throat of floral tube, sometimes exserted; anthers 2, parallel, longitudinally dehiscent; ovary free, superior, 1-locular; ovule 1, pendulous, style simple, nectary disc small or absent. Fruit indehiscent; embryo straight, oily.
40–50 genera and about 890 species, world-wide but predominantly in tropical and southern Africa and from South-east Asia to Australia; 9 genera with 105 species native to Australia.