Plants herbs, climbers, shrubs, or trees. Leaves usually alternatie, simple, usually with a membranous sheat (ochrea) uniting the stipules. Flowers radially symmetric, usally bisexual, sometimes unisexual, in racemes, heads, or panicles; tepals 3-6, arranged in 1 or 2 series, often enlarged in fruit; stamens 5-9, in 1 or 2 series, inserted at or near the perianth base; ovaries superior, 1-celled, with 1 ovule, placentation basal; styles 2-4, free or partly united. Fruits nutes, often trigonous; seeds with abundant endsperm.
The family Polygonaceae is cosmopolitan in its distribution, but most abundant in the northern hemsphere. It includes about 1050 spcies in about 50 genera.
The World Flora Online treats Persicaria as distinct from Polygonum. That taxonomic treatment is now being used in OpenHerbarium. All species of Polygonum included in the Flora of Somalia belong in Persicaria. The keys and descriptions have been modified to reflect the change.
