Annual or more rarely perennial herbs, glabrous or furnished with short and gland-like or multicellular hairs. Leaves alternate, long-petiolate, simple and entire or sinuate. Inflorescence basically cymose, bracteate, consisting entirely of dense to lax axillary cymose clusters or the upper clusters leafless and ± approximate to form a lax or dense “spike” or panicle. Flowers unisexual, dioecious or monoecious, bibracteolate; perianth segments (2-) 3-5, free or connate at the base, membranous, those of the female flowers slightly accrescent in fruit. Stamens free, usually similar in number to the perianth segments, with no alternating pseudostaminodes. Stigmas 2-3. Ovule solitary, erect. Fruit a dry capsule, indehiscent, irregularly rupturing or commonly dehiscing by a circumscissile lid. Seeds usually black and shining, testa thin; embryo annular, endosperm present.