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The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 12 extant division-level taxa within the Kingdom Plantae (Viridiplantae) and 10 within the extant land plants. Pinophytes are gymnosperms, cone-bearing seed plants with vascular tissue. All extant conifers are woody plants with secondary growth, the great majority being trees with just a few being shrubs. Typical examples of conifers include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews.〔Campbell, Reece, "Phylum Coniferophyta". Biology. 7th. 2005. Print. P. 595〕 The division contains approximately eight families, 68 genera, and 630 living species.〔(Catalogue of Life: 2007 Annual checklist - Conifer database ) 〕〔Lott, J., Liu, J., Pennell, K., Lesage, A., & West, M. (2002, September). Iron-rich particles and globoids in embryos of seeds from phyla Coniferophyta, Cycadophyta, Gnetophyta, and Ginkgophyta: characteristics of early seed plants. Canadian Journal of Botany, 80(9), 954–961. Retrieved July 17, 2009, from Academic Search Premier database.〕 Although the total number of species is relatively small, conifers are of immense ecological importance. They are the dominant plants over huge areas of land, most notably the boreal forests of the northern hemisphere,〔 but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptations. The narrow conical shape of northern conifers, and their downward-drooping limbs, help them shed snow. Many of them seasonally alter their biochemistry to make them more resistant to freezing, called "hardening". While tropical rainforests have more biodiversity and turnover, the immense conifer forests of the world represent the largest terrestrial carbon sink, i.e. where carbon from atmospheric is bound as organic compounds. They are also of great economic value, primarily for timber and paper production;〔〔 the wood of conifers is known as softwood. ''Conifer'' is a Latin word, a compound of ''conus'' (cone) and ''ferre'' (to bear), meaning "the one that bears (a) cone(s)". ==Evolution== The earliest conifers in the fossil record date to the late Carboniferous (Pennsylvanian) period (about 300 million years ago),〔Henry, R.J.(2005) Plant Diversity and evolution. London: CABI.〕 possibly arising from ''Cordaites'', a seed-bearing plant with cone-like fertile structures. This plant resembled the modern ''Araucaria''. Pinophyta, Cycadophyta, and Ginkgophyta all developed at this time.〔 An important adaptation of these gymnosperms was allowing plants to live without being so dependent on water. Other adaptations are pollen (so fertilization can occur without water) and the seed, which lets the embryo be transported and developed elsewhere.〔 Conifers appear to be one of the taxa that benefited from the Permian–Triassic extinction event. 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「Pinophyta」の詳細全文を読む スポンサード リンク
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