shrubs or twining, rarely trees. Stem often with swollen nodes, occasionally
geniculate. Leaves simple, mostly alternate, usually entire, seldom pinnately
or palmately cleft, sometimes auriculate at the base, stipules ocreate.
Inflorescence paniculate, capitate or axillary fascicles. Flowers pedicellate,
usually bisexual, primitively trimerous, sometimes pentamerous or rarely
dimerous. Tepals 2-6, basally united, green or coloured, persistent. Stamens
2-9, usually 6 in 2 cycles of 3. Carpels 2-4, syncarpous, ovary unilocular,
ovule solitary and basal. Fruit an achene or small nut, very often triangular.