Small trees, shrubs, shrublets or wiry herbs up to 6 m tall, evergreen, glabrous [or very rarely with simple hairs[[ch], without dark glands; branching below inflorescence lateral. Stems 4(6)-lined and ± compressed (ancipitous) when young, sooner or later becoming terete, eglandular; cortex exfoliating in strips or scales or irregularly; bark fissured, smooth. Leaves opposite, decussate, sessile to shortly petiolate, free or ± deeply united to form interfoliar ridge or very rarely bases of lamina proper united, base sometimes sheathing, deciduous at base or (more usually) above base or persistent and (in woody species) either fading or shed with cortex; lamina entire, with venation parallel or flabellate to pinnate or 1-veined, open or closed, with tertiary venation ± laxly reticulate; laminar glands punctiform; marginal gland dots dense, often very small; ventral resin glands absent. Inflorescence 1-flowered, with branching pseudo-dichotomous (usually from uppermost node) or 2-15-flowered and then with branching (within inflorescence) dichasial/monochasial from uppermost node, often with subsidiary branches from lower nodes; bracts and bracteoles foliar or reduced or sometimes transitional in form to sepals. Flowers stellate or occasionally obconic, homostylous. Sepals 5, free, persistent, erect in fruit, with margin entire; veins 3-11(-19); laminar glands hnear to punctiform; marginal, submarginal and inframarginal glands absent. Petals 5, persistent, with apiculus subterminal to obsolete, acute to acuminate or obtuse; margin entire; marginal glands absent; laminar glands linear to punctiform. Stamen fascicles basically 5, very rarely distinguishable individually, usually forming a continuous narrow ring of 5-250 stamens (i.e. 1-50 per fascicle) or very rarely fascicles ± united 2+2+1, persistent; filaments very shortly united or very rarely united above midway; anthers yellow to orange, gland amber; pollen type VIII. Ovary with 3-5 parietal placentae, ∞-ovulate; styles 3-5, free with bases contiguous; stigmas small to broadly capitate or clavate. Capsule 3-5-valved, coriaceous to chartaceous, with valves obscurely narrowly longitudinally vittate, occasionally with 1-3 flattish vesicles. Seeds narrowly cylindric, shallowly carinate or not, without apical expansion; testa scalariform-reticulate to ribbed-scalariform.