|Abstract||Herbs or undershrubs, usually succulent, perennial, less often annual or biennial. Leaves spirally arranged, opposite or whorled, exstipulate, simple or compound, entire, dentate, crenate, serrate or deeply incised. Flowers ♀, rarely unisexual, actinomorphic, usually cymose or cymose-paniculate, rarely spicate or solitary in leaf-axils, pedicelled or sessile, mostly 4—5-, rarely 3- or polymerous. Sepals free or nearly so, or united into a distinct tube, after anthesis marcescent and persistent as are the petals. Petals the same number as sepals, rarely more, hypogynous, free or variously connate. Stamens either as many as petals and alternate with them or twice their number, perigynous or all or partly inserted on the corolla; filaments free from each other; anthers 2-celled; cells introrse, dehiscing longitudinally. Hypogynous scales as many as carpels, placed singly at the back of them, free or at the base adnate to the base of the carpels. Carpels superior, the same number as petals, epipetalous, free or connate at the base, 1-celled. Ovules inserted on the adaxial side, mostly many, biseriate, rarely solitary or few. Styles as many as carpels, free, linear or subulate, short to long. Fruit follicular, membranous or leathery, opening on the adaxial side. Seeds minute, endosperm usually fleshy; embryo straight.|
Distr. About 20 genera and upwards of 700 spp., in the frigid, temperate and warm regions of Europe, Asia, Africa, northern and tropical America, rare in S. America and Australia, absent from Polynesia.