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''Annona'' is a genus of flowering plants in the pawpaw/sugar apple family, Annonaceae. It is the second largest genus in the family after ''Guatteria'', containing approximately 166〔(Species of Annona on The Plant List ). Retrieved 2013-05-28.〕 species of mostly neotropical and afrotropical trees and shrubs. The generic name derives from ''anón'', a Hispaniolan Taíno word for the fruit. Paleoethnobotanical studies have dated ''Annona'' exploitation and cultivation in the Yautepec River region of Mexico to approximately 1000 BC. It has several common names like (Graviola, Soursop ) and Guanabana to name a few. Currently, seven ''Annona'' species and one hybrid are grown for domestic or commercial use, mostly for the edible and nutritious fruits; several others also produce edible fruits. Many of the species are used in traditional medicines for the treatment of a variety of diseases, though their efficacy as a medicine has yet to be validated scientifically. Several annonacaeous species have been found to contain acetogenins, a class of natural compounds with a wide variety of biological activities. ==Description== ''Annona'' species are taprooted, evergreen or semideciduous, tropical trees or shrubs.〔 This fruit typically grows in areas which do not get below 28 degrees; Cuba, Jamaica, and the Philippines, however it has been known to grow in certain areas of Florida. *Trunks: The trunks have thin bark that has broad and shallow depressions or fissures which join together and are scaly giving rise to slender, stiff, cylindrical and tapering shoots with raised pores and naked buds.〔 *Leaves: Leaf blades can be leathery or thin and rather soft or pliable, bald or hairy.〔 *Flowers: The flowering stalks rise from axils, or occasionally from axillary buds on main stems or older stems, or as solitary flowers or small bundle of flowers. Usually, the three or four deciduous sepals are smaller than the outer petals that do not overlap while in bud. Six to eight fleshy petals in two whorls—the petals of the outer whorl are larger and do not overlap; inner petals are ascending and distinctively smaller, and nectar glands are darker pigmented. Numerous stamens that are ball, club-shaped, or curved and hooded or pointed beyond anther sac. Numerous pistils, attached directly to the base, are partially united to various degrees with distinct stigma, with one or two ovules per pistil; the style and stigma are club-shaped or narrowly conic.〔 *Fruits: One fleshy, ovate to spherical fruit is produced per flower. Each fruit consists of many individual small fruits or syncarps, with one syncarp and seed per pistil. Seeds are bean-like with tough coats; the seed kernels are toxic.〔 *Pollination: Dynastid scarab beetles appear basic within the genus ''Annona''. Those species of ''Annona'' which are more morphologically derived, as well as all ''Rollinia'' spp., possess reduced floral chambers and attract small beetles such as Nitidulidae or Staphylinidae. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Annona」の詳細全文を読む スポンサード リンク
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