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''Tetracentron'' is a genus of flowering plant, the sole living species being ''Tetracentron sinense''. It was formerly considered the sole genus in the family Tetracentraceae, though modern botanists include it in the family Trochodendraceae together with the genus ''Trochodendron''. It is native to southern China and the eastern Himalaya, where it grows at altitudes of 1100–3500 m in a temperate climate; it has no widely used common name in English, though is sometimes called "spur-leaf".〔(Spur-leaf (Tetracentron sinense) close-up of bark ). Alamy. Retrieved 16 March 2015〕 It is a tree growing to 20–40 m tall. The leaves are deciduous (the ''Flora of China'' reporting it as evergreen is an error), borne singly at the apex of short spur shoots, each leaf dark green, broad heart-shaped, 5–13 cm long and 4–10 cm broad, with a rugose surface and a serrated margin. The spur shoots bear a one leaf each year, slowly lengthening with each subsequent year. The flowers are inconspicuous, yellowish green, without petals, produced on slender catkins 10–15 cm long; each flower is 1–2 mm diameter. The fruit is a follicle 2–5 mm diameter, containing 4-6 seeds. ''Tetracentron'' shares with ''Trochodendron'' the feature, very unusual in angiosperms, of lacking vessel elements in its wood. This has long been considered a very primitive character, resulting in the classification of these two genera in a basal position in the angiosperms; however, research in Molecular phylogenetics by the Angiosperm Phylogeny Group and others has shown that these two genera are not basal angiosperms, but basal eudicots.〔Andreas Worberg, Dietmar Quandt, Anna-Magdalena Barniske, Cornelia Löhne, Khidir W. Hilu, and Thomas Borsch. 2007. "Phylogeny of basal eudicots: Insights from non-coding and rapidly evolving DNA." ''Organisms Diversity and Evolution'' 7(1):55-77. (see "External links" below).〕〔J. Gordon Burleigh, Khidir W. Hilu, and Douglas E. Soltis. 2009. "Inferring phylogenies with incomplete data sets: a 5-gene, 567-taxon analysis of angiosperms." BMC Evolutionary Biology 9(61). (see "External links" below).〕 This suggests that the absence of vessel elements is a secondarily evolved character, not a primitive one. ==Species== *†''Tetracentron atlanticum'' *†''Tetracentron piperoides'' *''Tetracentron sinense'' 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「Tetracentron」の詳細全文を読む スポンサード リンク
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