Annual herbs. Stems branching dichotomously from base. Leaves opposite or whorled with scarious stipules. Inflorescences cymose-paniculate; cymes head-like, made of 3 sessile flowers borne on a common peduncle; middle flower hermaphrodite, the lateral ones rudimentary, accompanied by plumosely parted sterile branchlets, elongating and indurating at maturity, enclosing fruit at dispersal. Sepals 5, linear-oblong, mucro¬nate. Petals 5. Stamens 5, united at base. Ovary 1-celled; ovule straight, semianatro¬pous; style long, curved, with 3 short stigmas. Fruit a scarious, 1-seeded, included utricle. Seeds erect with membranous coat; endosperm scanty; embryo straight.