| 翻訳と辞書 |
| Camissonia benitensis ： ウィキペディア英語版 |
Camissonia benitensis
''Camissonia benitensis'' is a species of evening primrose known by the common name San Benito evening primrose. It is endemic to California, where its range includes far southern San Benito County, far western Fresno County, and far eastern Monterey County. The species is categorized as a strict serpentine endemic, meaning that it is always found growing on serpentine soils; however, at least four populations of the species are known to occur on shale substrates. Serpentine is an ultramafic rock. It weathers to produce soils with characteristically low levels of nutrients like nitrogen, phosphorus, potassium, and calcium, and high levels of magnesium and heavy metals including nickel and chromium. A major, consistent chemical feature of serpentine soil is a bioavailable calcium:magnesium ratio much less than 1. Most nonserpentine soils have a ratio far greater than 1 (more calcium and much less magnesium). The extreme chemical characteristics of serpentine soils give rise to uniquely adapted and rare serpentine endemic plant species such as ''C. benitensis''.
==Description==
''Camissonia benitensis'' was discovered by Peter H. Raven on a serpentine stream terrace adajcent to Clear Creek (New Idria serpentine mass; Bureau of Land Management Clear Creek Management Area) in 1960 and scientifically described by him in 1969. The plant's specific epithet, "''benitensis''", commemorates its discovery in San Benito County. It is a diminutive annual herb that rarely grows larger than 10 centimeters in field conditions, but can become multi-branched and exceed 30 centimeters in diameter within a horticultural setting. Its reddish stems bear plentiful linear leaves less than 1 centimeter long and minutely toothed along the edges. Plants bear four-petaled yellow flowers approximately 6 millimeters in diameter. Flowering occurs in April and May, opening in the morning and closing in early afternoon. The species is fully self-pollinating.〔USFWS. (''Camissonia benitensis'' Five-year Review. ) August 2009.〕〔Taylor, D. W. (1990). Ecology and life history of the San Benito evening primrose. Bureau of Land Management, California State Office.〕 The fruit is a cylindrical capsule up to 4 centimeters in length. The fruits remain largely closed at maturity and spring open upon wetting with the first fall rains, dispersing seeds. Seeds are tiny (1 millimeter long, 0.5 millimeter wide) and black to brown in color. The seeds have a smooth seed coat and weigh approximately 0.1 milligram each. Long-distance dispersal likely occurs as seeds in mud stuck to animals or vehicles. Seeds germinate with the first rains in fall or winter.
''Camissonia benitensis'' bears a close resemblance to ''Camissonia contorta''.〔USFWS. (Determination of threatened status for ''Camissonia benitensis''. ) ''Federal Register'' February 12, 1985.〕 The two species are virtually indistinguishable with the naked eye when plants are small (under 6 centimeters), as is common in their native habitat, where they occur together. ''Camissonia strigulosa'' also grows in this range but is distinguishable by its smaller flowers and prostrate habit. They dichotomous keys in The Jepson Manual first edition are not detailed enough to make certain positive identifications. One key characteristic that can help distinguish the three species is the morphology of the trichomes on the distal inflorescences. ''C. contorta'' has trichomes that look like transparent glassy rods. ''C. strigulosa'' has white linear or lance-shaped blades. ''C. benitensis'' has both kinds of trichomes. This key characteristic was lacking in Jepson Manual first edition, but is now included in Jepson Manual second edition.〔
A ''Camissonia'' which resembles either ''C. contorta'' or ''C. benitensis'' growing on serpentine soil in upland geologic transition zone habitat or serpentine stream terrace habitat ''within'' serpentine masses is virtually always ''C. benitensis''.〔 A ''Camissonia'' resembling either of the two species on serpentine stream terraces ''outside of'' serpentine masses or mixed alluvium stream terraces could be either ''C. contorta'' or ''C. benitensis''.〔 ''C. strigulosa'' is the common ''Camissonia'' species found growing on nonserpentine alluvial stream and river deposits within the range of ''C. benitensis''.
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「Camissonia benitensis」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|