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Nyctaginaceae (bougainvilleas) A family of herbs, shrubs, and trees that have opposite or alternate, simple leaves with no stipules. The inflorescence is cymose, with bisexual or unisexual flowers sometimes surrounded by coloured bracts resembling a calyx. The sepals are petal-like and tubular. There are no petals. Usually 5 stamens alternate with the lobes of the calyx. The ovary is superior with a single carpel, a single ovule, and a long style. The fruit is an achene, sometimes enclosed by the persistent calyx. The seeds contain endosperm, perisperm, and embryo. Several Bougainvillea species are used as hedging plants in warm temperate regions, and many of the species of the family are cultivated as ornamentals. Several species are used in medicine, e.g. Mirabilis jalapa, which gives a purgative drug. There are 34 genera, comprising about 350 species. They are found throughout the tropical regions of the world, but more than 200 of the species are centred in America.