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Xyridaceae A family of monocotyledonous (see MONOCOTYLEDON), herbaceous plants, which are mostly perennial. They are rush-like marsh plants with radical, sheathing leaves, and dense spikes or heads of flowers. The leaves are linear and cylindrical, or with narrow, flat blades. The flowers are bisexual and held in the axil of a stiff bract. The inner of the 3 sepals forms a hood over the petals, while the others are keeled. The corolla is a tube with 3 lobes, and is usually yellow in colour. The stamens are held opposite the corolla lobes and are attached to the tube. The ovary is superior, with the 3 carpels fused to form a single locule with many ovules, and a 3-lobed style. The corolla remains on the seed capsule. There are 5 genera, with about 260 species, distributed mainly throughout tropical and subtropical regions, and centred in America.