Annual herb with alternate branches and leaves; leaves entire. Flowers small, in long-pedunculate, axillary, spike-like bracteate racemes, each bract subtending a very shortly pedunculate partial inflorescence consisting of a central fertile flower and two highly modified, sterile, unibracteolate lateral flowers. Perianth segments 4-5, the outer pair opposite and sheathing the remaining flower parts, the inner segments much more delicate and hyaline. Stamens 4-5, free, without intermediate staminode-like teeth, filaments filiform. Style filiform; stigmas 2, divergent. Ovary with a single ovule lateral on a curved funicle, radicle descending. Fruit a hard, indehiscent nutlet enclosed by the persistent perianth and falling together the sterile flowers and bracteoles. Endosperm copious.