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The Asparagales are an order of plants, and on this page the structure of the order is used according to the APG III system. The order takes its name from the family Asparagaceae and is placed in the monocots. The order is clearly circumscribed on the basis of DNA sequence analysis, but is difficult to define morphologically, since its members are structurally diverse. The APG III system is used in ''World Checklist of Selected Plant Families'' from the Royal Botanical Gardens at Kew. With this circumscription, the order consists of 14 families (Dahlgren had 31) with approximately 1120 genera and 26000 species. Thus although most species in the order are herbaceous, some no more than 15 cm high, there are a number of climbers (e.g., some species of ''Asparagus''), as well as several genera forming trees (e.g. ''Agave'', ''Cordyline'', ''Yucca'', ''Dracaena''), some of which can exceed 10 m in height. Succulent genera occur in several families (e.g. ''Aloe''). One of the defining characteristics of the order is the presence of phytomelan (phytomelanin), a black pigment present in the seed coat, creating a dark crust. Phytomelan is found in most families of the Asparagales (although not in Orchidaceae, thought to be a sister to the rest of the group). Almost all species have a tight cluster of leaves (a rosette), either at the base of the plant or at the end of a more-or-less woody stem; the leaves are less often produced along the stem. The flowers are in the main not particularly distinctive, being of a general 'lily type', with six tepals, either free or fused from the base. From an economic point of view, the order Asparagales is second in importance within the monocots to the order Poales (which includes grasses and cereals). Species are used as food and flavourings (e.g. onion, garlic, leek, asparagus, vanilla), as cut flowers (e.g. freesia, gladiolus, iris, orchids), and as garden ornamentals (e.g. day lilies, lily of the valley, ''Agapanthus''). == Families included in the APG == Order Asparagales Link * Family Amaryllidaceae J.St.-Hil. (including Agapanthaceae F.Voigt, Alliaceae Borkh.)〔The name 'Alliaceae' has also been used for the expanded family comprising the Alliaceae ''sensu stricto'', Amaryllidaceae and Agapanthaceae (e.g. in the APG II system). 'Amaryllidaceae' is used as a conserved name in APG III.〕 * Family Asparagaceae Juss. (including Agavaceae Dumort. * Family Asteliaceae Dumort. * Family Blandfordiaceae R. Dahlgren & Clifford * Family Boryaceae M.W. Chase, Rudall & Conran * Family Doryanthaceae R. Dahlgren & Clifford * Family Hypoxidaceae R.Br. * Family Iridaceae Juss. * Family Ixioliriaceae Nakai * Family Lanariaceae R. Dahlgren & A.E.van Wyk * Family Orchidaceae Juss. * Family Tecophilaeaceae Leyb. * Family Xanthorrhoeaceae Dumort. (including Asphodelaceae Juss. and Hemerocallidaceae R.Br.) * Family Xeronemataceae M.W. Chase, Rudall & M.F.Fay The earlier 2003 version, APG II, allowed 'bracketed' families, i.e. families which could either be segregated from more comprehensive families or could be included in them. These are the families given under "including" in the list above. APG III does not allow bracketed families, requiring the use of the more comprehensive family; otherwise the circumscription of the Asparagales is unchanged. A separate paper accompanying the publication of the 2009 APG III system provided subfamilies to accommodate the families which were discontinued. The first APG system of 1998 contained some extra families, included in square brackets in the list above. 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「Families of Asparagales」の詳細全文を読む スポンサード リンク
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