Gramineae

Annual or perennial herbs, rarely shrubby. Leaves alternate, consisting of sheath, ligule and blade. Sheaths envelopping the stem, usually with free margins; ligule borne at the mouth of the sheath, membranaceous or a rim of hairs; blades mostly elongate, flat, convolute or terete, parallel-veined. Inflorescence spicate, racemose or paniculate, bearing spikelets which consist of a shortened axis (rhachilla) and two to many scales. The two lowest scales (glumes) empty, rarely wanting; the following scales (lemmas) bearing in their axil an usually enclosed prophyll (palea) and a perfect or reduced flower. Lemma, palea and flower together forming the floret. Perfect flower consisting of 2—3 hyaline or fleshy lodicules, usually 3 (1—6) stamens and a pistil. Stamens with at anthesis rapidly elongating, filiform or ribbon-like filaments with 2-celled anthers, opening with longitudinal splits. Ovary superior, 1-celled; ovule one, anatropous; styles usually 2(1—3) with plumose stigmas. Fruit a caryopsis (i.e. the pericarp adnate to the seed) with mealy endosperm, rarely a nut, a berry or an utricle with free pericarp. Embryo small, at the base of the side opposite the hilus. About 4000 species in 500 genera; of world-wide distribution