|
''Xanthisma coloradoense'' (syn. ''Aster coloradoensis'', ''Machaeranthera coloradoensis'')〔(''Xanthisma coloradoense''. ) Flora of North America.〕 is a species of flowering plant in the aster family known by the common name Colorado tansyaster. It is native to Colorado and Wyoming in the United States.〔Beatty, B.L., W.F. Jennings, and R.C. Rawlinson (2004, January 30). (''Machaeranthera coloradoensis'' (Gray) Osterhout (Colorado tansyaster): a technical conservation assessment. ) (). USDA Forest Service, Rocky Mountain Region.〕 This cushion plant〔 is a perennial herb growing from a taproot and branching caudex. It grows up to 14 centimeters tall, with several to many thick, hairy stems. The hairy leaves are lance-shaped to spatula-shaped and the edges are lined with large, sharp teeth tipped with bristles. The inflorescence is a solitary flower head with narrow, white-tipped phyllaries. It contains pink or purple ray florets up to 1.5 centimeters long and many disc florets. The fruit may be nearly a centimeter long including its pappus.〔〔 There were previously two varieties of this species, but these subtaxa are no longer recognized.〔〔 This plant may hybridize with ''Xanthisma grindelioides''.〔〔 This plant grows in mountains, often in an alpine climate. Habitat types include grassland, pinyon-juniper woodland, and alpine fellfield. It grows in open areas. There is often little vegetative cover and the terrain is rocky. Associated species in the habitat may include pines ''Pinus'' spp., shrubs such as ''Cercocarpus montanus'' and ''Chrysothamnus'' spp., other plants such as ''Astragalus'' spp., ''Erigeron'' spp., ''Potentilla'' spp., ''Festuca'' spp., and ''Elymus'' spp., and lichens such as members of genus ''Xanthoparmelia''. It can be found growing with some rare species, including ''Astragalus molybdenus''.〔 Threats to this species are not well known because the plant has not been studied enough yet.〔 Potential threats include recreational activity such as off-road vehicle use, invasive species, grazing and trampling by livestock, and energy development, particularly wind power.〔(''Machaeranthera coloradoensis''. ) NatureServe.〕 ==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「Xanthisma coloradoense」の詳細全文を読む スポンサード リンク
|