Polygonaceae
Polygonaceae Juss. comprises approximately 55–60 genera and 1,200–1,300 species, distributed worldwide, particularly in temperate regions of the Northern Hemisphere. Molecular phylogenetic studies support the monophyly of Polygonaceae and have clarified relationships among major tribes and genera, including Polygonum, Persicaria, Rumex, Fagopyrum, and Rheum. Members are characterized by swollen nodes, alternate leaves with an ochrea, small flowers, superior ovaries, and one-seeded fruits (achenes).
Key characteristics
- Herbs, shrubs, or climbers
- Stems jointed with swollen nodes
- Leaves alternate, simple
- Ochrea (stipular sheath) present
- Flowers small with petaloid tepals
- Ovary superior
- Fruit a three-angled or lenticular achene
- Seeds solitary
Distribution
Polygonaceae has a nearly cosmopolitan distribution, with greatest diversity in temperate regions of Eurasia and North America. Members occur in grasslands, forests, wetlands, alpine meadows, riverbanks, deserts, coastal habitats, agricultural fields, and disturbed sites, from sea level to high mountains. In Pakistan, Polygonaceae is widely distributed throughout, the Salt Range, Potohar Plateau, Hindu Kush, Karakoram, and Himalayan regions. Species occur in cultivated fields, wetlands, riverbanks, alpine meadows, mountain slopes, roadsides, rangelands, and saline habitats. Common genera include Polygonum, Persicaria, Rumex, Rheum, Fagopyrum, and Calligonum.