Herbs, shrubs or climbers, rarely trees. Leaves alternate or rarely opposite or whorled, simple, with stipules sometimes dilated into a membraneous sheath above the swollen node. Flowers mostly perfect, small, rarely solitary. Calyx +/- persistent, 2-6-cleft or –parted, in 1 or 2 series, often petaloid. Petals 0. Stamens usually 6-9, inserted near the base of the calyx. Pistil solitary, superior, mostly 1-celled; styles 2-4, usually free. Ovule 1, basal. Fruit a lenticular or angled achene, sometimes enclosed in the ripening perianth which may become fleshy. (Munz, Flora So. Calif. 670).
About 30-40 genera and 800 species, widely distributed in cold and temperate regions. A few species are used for ornament and food (Rheum, rhubarb; Fagopyrum, buckwheat; etc.). (Munz, Flora So. Calif. 670).