LXXI.—Polygonaceæ.—Herbs or shrubs. Leaves alternate, entire, stipules usually sheathing. Flowers small and usually bisexual. Perianth-segments 3-6, persistent. Stamens usually 5-8, opposite the perianth-segments. Ovary 1-celled, free, compressed or trigenous, ovule 1. Fruit a nut, enclosed in the perianth.