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| diversity = Well over 2600 species in some 202 genera | diversity_link = list of Arecaceae genera | parent_authority= Bromhead | authority = Bercht. & J.Presl, nom. cons.〔 }} The Arecaceae are a botanical family of perennial lianas, shrubs, and trees commonly known as palm trees. (Owing to historical usage, the family is alternatively called Palmae or Palmaceae.)〔"Palmaceae" is not accepted because the name Arecaceae (and its acceptable alternative Palmae, (ICBN Art. 18.5 )) are conserved over other names for the palm family.〕 They are flowering plants, the only family in the monocot order Arecales. Roughly 200 genera with around 2600 species are currently known, most of them restricted to tropical, subtropical, and warm temperate climates. Most palms are distinguished by their large, compound, evergreen leaves arranged at the top of an unbranched stem. However, many palms are exceptions, and in fact exhibit an enormous diversity in physical characteristics. As well as being morphologically diverse, palms also inhabit nearly every type of habitat within their range, from rainforests to deserts. Palms are among the best known and most extensively cultivated plant families. They have been important to humans throughout much of history. Many common products and foods are derived from palms, and palms are also widely used in landscaping, making them one of the most economically important plants. In many historical cultures, palms were symbols for such ideas as victory, peace, and fertility. For inhabitants of cooler climates today, palms symbolize the tropics and vacations.〔(Landscaping with Palms in the Mediterranean )〕 ==Morphology== Whether as shrubs, trees, or vines, palms have two methods of growth: solitary or clustered. The common representation is that of a solitary shoot ending in a crown of leaves. This monopodial character may be exhibited by prostrate, trunkless, and trunk-forming members. Some common palms restricted to solitary growth include ''Washingtonia'' and ''Roystonea''. Palms may instead grow in sparse though dense clusters. The trunk develops an axillary bud at a leaf node, usually near the base, from which a new shoot emerges. The new shoot, in turn, produces an axillary bud and a clustering habit results. Exclusively sympodial genera include many of the rattans, ''Guihaia'', and ''Rhapis''. Several palm genera have both solitary and clustering members. Palms which are usually solitary may grow in clusters, and ''vice versa''. These aberrations suggest the habit operates on a single gene.〔Uhl, Natalie W. and Dransfield, John (1987) ''Genera Palmarum - A classification of palms based on the work of Harold E. Moore''. Lawrence, Kansas: Allen Press. ISBN 0-935868-30-5 / ISBN 978-0-935868-30-2〕 Palms have large, evergreen leaves that are either palmately ('fan-leaved') or pinnately ('feather-leaved') compound and spirally arranged at the top of the stem. The leaves have a tubular sheath at the base that usually splits open on one side at maturity.〔(Arecaceae - University of Hawaii Botany )〕 The inflorescence is a spadix or spike surrounded by one or more bracts or spathes that become woody at maturity. The flowers are generally small and white, radially symmetric, and can be either uni- or bisexual. The sepals and petals usually number three each, and may be distinct or joined at the base. The stamens generally number six, with filaments that may be separate, attached to each other, or attached to the pistil at the base. The fruit is usually a single-seeded drupe (sometimes berry-like)〔(Arecaceae in Flora of North America )〕 but some genera (e.g. ''Salacca'') may contain two or more seeds in each fruit. The Arecaceae are notable among monocots for their height and for the size of their seeds, leaves, and inflorescences. ''Ceroxylon quindiuense'', Colombia's national tree, is the tallest monocot in the world, reaching up to 60 m tall.〔(:: Presidencia de la República de Colombia :: )〕 The ''coco de mer'' (''Lodoicea maldivica'') has the largest seeds of any plant, 40–50 cm in diameter and weighing 15–30 kg each. Raffia palms (''Raphia'' spp.) have the largest leaves of any plant, up to 25 m long and 3 m wide. The ''Corypha'' species have the largest inflorescence of any plant, up to 7.5 m tall and containing millions of small flowers. ''Calamus'' stems can reach 200 m in length. 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「Arecaceae」の詳細全文を読む スポンサード リンク
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