|
''Trifolium friscanum'' is a rare species of flowering plant in the legume family known by the common name Frisco clover. It is endemic to the US state of Utah, where it is known only from Beaver and Millard Counties. It was originally described as a variety of ''Trifolium andersonii'' in 1978, but was elevated to species status in 1993.〔(US Fish and Wildlife Service Species Assessment and Listing Priority Assignment Form. ) USFWS.〕 It occurs over away from the nearest ''T. andersonii''.〔''(Trifolium friscanum. )'' NatureServe.〕 Most individuals live in the San Francisco Mountains, where the highest point is called Frisco Peak.〔Lanner, R. M. and R. Warnick. (1971). (Conifers of the San Francisco Mountains, San Rafael Swell, and Roan Plateau. ) ''Great Basin Naturalist'' 31:3 177.〕 This is a low-growing dwarf plant with a taproot and woody stem. It is no more than tall. Each leaf is made up of three leaflets coated in silvery hairs. The inflorescence contains 4–9 reddish purple flowers.〔〔 This plant grows in pinyon-juniper and sagebrush ecosystems. Other plants in the habitat include ''Ephedra'' spp. (Mormon tea), ''Gutierrezia sarothrae'' (snakeweed), ''Cercocarpus intricatus'' (dwarf mountain-mahogany), and ''Petradoria pumila'' (rock goldenrod). The local region is home to other rare plants, including ''Eriogonum soredium'' (Frisco buckwheat) and ''Lepidium ostleri'' (Ostler’s peppergrass).〔 Frisco clover is known as a "narrow endemic" because it grows on a particular substrate: gravelly and bouldery volcanic soils, Ordovician limestone, and dolomite.〔 There are only five populations of this plant.〔 The total population of the plant is not certain because it is difficult to count individuals of this mound-forming species. Also, some occur on private property where access is restricted.〔Tilley, D. 2012. (Plant Guide for Frisco clover (''Trifolium friscanum''). ) USDA-Natural Resources Conservation Service, Aberdeen, ID Plant Materials Center.〕 The main two threats to the species' survival are mining and nonnative species. Mining has occurred in the region for a long time, as the substrates are rich in silver, zinc, lead, gold, and copper. Gravel quarrying has also occurred. There are many old mine shafts in the area. Most mining has ceased now, but some local areas are vulnerable to continuing mining activity. Three of the five remaining populations of the plant are located at mining sites.〔 Introduced plant species are also a threat to this species. The most notorious is ''Bromus tectorum'', cheatgrass. It grows in the area, and the aforementioned mining activity actually encourages its spread. Cheatgrass encourages fire in this area, which is not fire-adapted.〔 ==References== 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「trifolium friscanum」の詳細全文を読む スポンサード リンク
|