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American pokeweed (''Phytolacca americana''), or simply pokeweed, is a herbaceous perennial plant in the pokeweed family Phytolaccaceae growing up to in height. It is native to the eastern United States and has significant toxicity. It has simple leaves on green to purplish stems and a large white taproot. The flowers are green to white, followed by purple to almost black berries which are a food source for songbirds such as gray catbird, northern mockingbird, northern cardinal, and brown thrasher, as well as other birds and some small animals (i.e., to species that are unaffected by its human toxins). ''P. americana'' or pokeweed—also known by a number of other names—is native to eastern North America, the Midwest, and the Gulf Coast, with more scattered populations in the far West. It is considered a major pest species by farmers, and that and the danger of human poisoning—its significant toxicity and its risks to human and animal health are consistently reported, with the whole of the plant toxic and increasing in toxicity through the year, with children at particular risk of its very poisonous purple-red ripe fruit—support arguments for eradication of ''P. americana.'' Even so, it is used as an ornamental in horticulture, and it provokes interest for the variety of its natural products (toxins and other classes), for its ecological role, its historical role in traditional medicine, and for some utility in biomedical research (e.g., in studies of pokeweed mitogen). In the wild, it is easily found growing in pastures, recently cleared areas, and woodland openings, edge habitats such as along fencerows, and in waste places. ==General description== Pokeweed is a member of the Phytolaccaceae, or broader pokeweed family, and is a native herbaceous perennial plant,〔 a semi-succulent that is large, growing up to in height.〔 It presents branches, sometimes several, growing from the crown of a thick, white, fleshy taproot, each a "stout, smooth, green to somewhat purplish stem;" simple, entire leaves with long leafstalks alternate along the stem.〔 Pokeweeds reproduce only by its seeds (large glossy black, and lens-shaped), contained in a fleshy, 10-celled, purple-to-near-black berry with crimson juice. The flowers are perfect, radially symmetric, white or green, with 4-5 sepals and no petals. The flowers develop in elongated clusters termed racemes.〔〔Per Owen, the flower structure contains "10 separate stamens with 10 carpels united into a 10-cell pistil," that gives rise to the 10-celled berry, see Owen, 1988, op. cit.〕 The seeds have a long viability and can germinate after many years in the soil. Birds are unaffected by the natural chemicals contained in the berries (see below), and eat them, scattering the seeds, though they are also found adventitiously in commercial seed (e.g., vegetable seed packets).〔 The berries are reported to be a good food source for songbirds and other bird species and small animals unaffected by its toxins.〔Nancy L. Matthews, 1987, "Appendix F: Habitat Assessment Manual," in ''Report: Anne Arundel Co., Offc. Planning and Zoning, Environmental and Special Projects Div., to Office of Coastal Resources Management, NOAA and State of Maryland Chesapeake Bay Critical Area Commission,'' August 1987, 9 pages, ''passim'' see (), accessed 2 May 2015.〕 Distribution via birds is thought to accounts for the appearance of "single, isolated plants" in areas that had otherwise not been populated by pokeweed.〔 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「Phytolacca americana」の詳細全文を読む スポンサード リンク
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