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''Isotria medeoloides'' (small whorled pogonia or little five leaves) is a terrestrial orchid found in temperate Eastern North America. Its range is from southern Maine south to Georgia and west to southern Ontario, Michigan, and Tennessee. A population was found in Missouri in 1897,〔(Small whorled pogonia. ) Missouri Conservationist.〕 but the plant is no longer believed extant there.〔USFWS. (''Isotria medeoloides'' Five-year Review. ) October 2008.〕 It has always been considered a rare species, often legendarily so. It has been called "the rarest orchid east of the Mississippi.〔(''Isotria medeoloides''. ) Center for Plant Conservation.〕 This is a rhizomatous herb producing a waxy gray-green stem up to about 25 centimeters tall. The gray-green leaves are up to 8.5 centimeters long by 4 wide and are borne in a characteristic whorl. The flower has green and green-streaked yellowish petals measuring between 1 and 2 centimeters long.〔(''I. medeoloides''. ) Flora of North America.〕 The plant's habitat includes hardwood or conifer-hardwood forests, where it is found in leaf litter along small "braided" intermittent streams. The plant is listed as a threatened species by the U.S. Fish and Wildlife Service, having been downlisted from endangered status in 1994 as more populations were discovered and several were given protection.〔 It is listed as an endangered species by most states or provinces within its range.〔(USDA Plants Profile )〕 There are about 104 populations known to exist, but most of these are small, containing fewer than 25 plants.〔 This orchid is sometimes confused with the common Indian cucumber (''Medeola virginiana''), which has similar whorled leaves and grows in similar habitat types. The species name ''medeoloides'' is a reference to this similarity.〔 Anecdotal tales of the species only appearing at decades-long intervals do not appear to be supported by field studies. The plant can usually remain dormant for up to three years.〔 The main threat to the species' existence is the destruction of its habitat.〔 Other threats include wild pigs, off-road vehicles, predation by deer and slugs, vandalism, and collection.〔USFS. (''I. medeoloides''. ) Celebrating Wildflowers.〕 == Notes == 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「Isotria medeoloides」の詳細全文を読む スポンサード リンク
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