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''Taxodium'' 〔''Sunset Western Garden Book,'' 1995:606–607〕 is a genus of one to three species (depending on taxonomic opinion) of extremely flood-tolerant conifers in the cypress family, Cupressaceae. The generic name is derived from the Latin word ''taxus'', meaning "yew", and the Greek word ''εἶδος'' (''eidos''), meaning "similar to." Within the family, ''Taxodium'' is most closely related to Chinese Swamp Cypress (''Glyptostrobus pensilis'') and Sugi (''Cryptomeria japonica''). Species of ''Taxodium'' occur in the southern part of the North American continent and are deciduous in the north and semi-evergreen to evergreen in the south. They are large trees, reaching tall and (exceptionally ) trunk diameter. The needle-like leaves, long, are borne spirally on the shoots, twisted at the base so as to appear in two flat rows on either side of the shoot. The cones are globose, diameter, with 10-25 scales, each scale with 1-2 seeds; they are mature in 7–9 months after pollination, when they disintegrate to release the seeds. The male (pollen) cones are produced in pendulous racemes, and shed their pollen in early spring. ''Taxodium'' species grow pneumatophores, or cypress roots, when growing in or beside water; these are woody projections which rise above the water and are said to help carry oxygen to the root systems. == Species == The three extant taxa of ''Taxodium'' are treated here as distinct species, though some botanists treat them in just one or two species, with the others considered as varieties of the first described. The three are distinct in ecology, growing in different environments, but hybridise where they meet. *''Taxodium ascendens'' Brongn. – Pond Cypress The Pond Cypress occurs within the range of Bald Cypress, but only on the southeastern coastal plain from North Carolina to Louisiana. It occurs in still blackwater rivers, ponds and swamps without silt-rich flood deposits. *''Taxodium distichum'' (L.) Rich. – Bald Cypress The most familiar species in the genus is the Bald Cypress, native to much of the southeastern United States, from Delaware to Texas, especially Louisiana and inland up the Mississippi River to southern Indiana. It occurs mainly along rivers with silt-rich flood deposits. *''Taxodium mucronatum'' Ten. – Montezuma Cypress, Ahuehuete The Montezuma Cypress occurs from the Lower Rio Grande Valley south to the highlands of Guatemala, and differs from the other two species in being substantially evergreen. A specimen in Santa María del Tule, Oaxaca, the Árbol del Tule, is tall and has the greatest trunk thickness of all trees, in diameter. It is a riparian tree, occurring on the banks of streams and rivers, not in swamps like the Bald and Pond Cypresses. *†''Taxodium dubium'' (Sternb.) Heer 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「taxodium」の詳細全文を読む スポンサード リンク
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