Poaceae
Poaceae Barnhart (syn. Gramineae) comprises approximately 780–800 genera and 12,000–12,500 species, making it one of the largest families of flowering plants. Molecular phylogenetic studies have confirmed its monophyly and clarified relationships among the major subfamilies, including Pooideae, Panicoideae, Bambusoideae, Chloridoideae, Ehrhartoideae, and Oryzoideae. Members are distinguished by hollow jointed culms, sheathing leaves with ligules, spikelet-based inflorescences, wind pollination, and one-seeded caryopses.
Key characteristics
- Annual or perennial grasses; rarely woody (bamboos)
- Culms usually hollow with swollen nodes
- Leaves alternate, two-ranked, with sheath, ligule, and blade
- Parallel venation
- Inflorescence composed of spikelets
- Flowers highly reduced and wind-pollinated
- Ovary superior with one ovule
- Fruit a caryopsis (grain)
Distribution
Poaceae has a cosmopolitan distribution, occurring on every continent, including Antarctica (as introduced species). Members occupy grasslands, forests, deserts, wetlands, alpine meadows, coastal dunes, agricultural fields, and aquatic habitats, from sea level to high mountains. The family dominates the world's temperate and tropical grasslands. Poaceae is one of the most widespread plant families in Pakistan, occurring throughout, the Potohar Plateau, Salt Range, Thal Desert, Cholistan Desert, Indus plains, and Himalayan regions. Species inhabit croplands, rangelands, wetlands, riverbanks, forests, alpine meadows, sand dunes, saline soils, and disturbed habitats. Major cereal and native genera include Triticum, Oryza, Hordeum, Avena, Zea, Sorghum, Pennisetum, Cenchrus, Cynodon, Bambusa, Phragmites, and Saccharum.