Gramineae

Gramineae The grass family; a very large and important family of monocotyledons, most of which are annual or perennial herbs, but a few genera (e.g. the bamboos) of which are woody. From an ecological viewpoint, it is the most successful family of flowering plants. Where forests have been destroyed by humans, grasses have tended to replace the trees as the dominant vegetation of many areas of the world. Economically, the Gramineae is the family of plants most important to humans, as it contains numerous cereal grasses (e.g. wheat, barley, oats, maize, rice, and millet, the staple foods of most of the world's population). Many grasses are important sources of fibres. Most grasses have hollow stems with solid points (nodes) capable of intercalary growth, and leaves in two opposite and alternating rows. Each leaf consists of a sheath round the stem, a blade, and usually a flap or ligule at the junction of sheath and blade. Inflorescences are very varied but are usually composed of units (spikelets) with a pair of sterile glumes at the base of each spikelet. Each spikelet consists of 1 to many florets, each floret normally having 2 subtending scales (the lower chaffy lemma and the upper membranaceous palea), 3 stamens with long filaments and flexible anthers (adapted to wind-pollination), and an ovary with 1 ovule and 2 long, feathery stigmas. There are 737 genera, with about 7950 species, distributed throughout the world.