Monoecious, rarely dioecious herbs or shrubs. Leaves 3-costate, alternate or opposite, entire; stipules free lateral, scarious or glumaceous, often persistent. Inflorescence axillary, cymose sessile clusters. Male flowers pedicellate, bracteolate; female sessile to shortly pedicelled. Calyx (3-)4-5-lobed in male flowers, lobes valvate, acute or acuminate, concave or abruptly inflexed and transversely plicate outside; tubular-ventricose, with 2-4-teeth at beaked and narrowed mouth in female flowers. Stamens as many as calyx lobes. Ovary free from calyx; style terminal, filiform, laterally villous and stigmatic, deciduous. Achenes shining, ovoid, enveloped by hardly changed or rarely winged or ribbed calyx.