| 词条 | Thelypodium howellii |
| 释义 |
|image = Thelypodium howellii spectabilis.jpg |image_caption = Thelypodium howellii spectabilis |status = G2 |status_system = TNC |genus = Thelypodium |species = howellii |authority = S. Wats. }} Thelypodium howellii, the Howell's thelypody[1] or Howell's thelypodium, is a rare plant of the Western United States. It is endemic to a relatively small area on the borders of three western States: Oregon, Nevada, and California. DescriptionThe Thelypodium howellii plant is biennial. It is often somewhat hairy, especially near the base, but may be hairless and waxy in texture. It produces a slender, branching, erect stem up to 70 centimeters tall. The leaves are mostly located in a rosette around the base. Leaves located higher on the stem may have clasping bases. The inflorescence is a raceme of widely spaced flowers with greenish white or purplish sepals and pale blue or purple, spoon-shaped petals. The fruit is a silique up to 4.5 centimeters long containing plump brown seeds.[2][3][4][5][6] Subspecies
Distribution, habitat, and ecologyThis plant is endemic to a small area stretching from north-eastern Oregon to north-eastern California.[6] It lives in alkaline or adobe meadows and seeps, river valleys and moist plains in Great Basin sagebrush scrub.[2] The fire ecology of this plant is not known at present. Conservation status and threatsU.S. Forest Service Pacific Southwest Region Sensitive Species. California Native Plant Society List 1B.2. NatureServe California State Rank: S2.2; Global Rank: G2 The threats facing Howell's thelypody are not known at present. Field identificationHowell's thelypody flowers from May to July. Var. spectabilis, known only from Malheur Co., Oregon, is larger than var. howellii, has larger, more strongly purple flowers, and is a federally listed species.[6] References1. ^{{PLANTS|id=THHO|taxon=Thelypodium howellii|accessdate=9 December 2015}} 2. ^1 {{cite web | title =Howell's Thelypodium | work = Eagle Lake Field Office | publisher =U.S. Department of Interior, Bureau of Land Management | url =http://www.blm.gov/ca/pa/ssp/plants/thelypodium_howellii.html | accessdate =2007-05-01 |archiveurl = https://web.archive.org/web/20070614191959/http://www.blm.gov/ca/pa/ssp/plants/thelypodium_howellii.html |archivedate = 2007-06-14}} 3. ^{{cite journal | author = Payson, Edwin Blake| year = 1922| title = Study of Thelypodium and its Immediate Allies| journal = Annals of the Missouri Botanical Garden| volume = 9| issue = 3| pages = 265–266| doi=10.2307/2990054}} 4. ^{{cite book | last = Schofield| first = W.B.| year = 2002| title = Field Guide to the Liverwort Genera of Pacific North America|publisher = University of Washington Press| pages = 181}} 5. ^{{cite book| last = Rollins| first = Reed C.| year = 1993| title = The Jepson Manual: Higher Plants of California|editor = Hickman, James C.|publisher = University of California Press|pages = 444–446}} 6. ^1 2 {{cite book | last = Hitchcock | first = C. Leo |author2=Arthur Cronquist |author3=Marion Ownbey |author4=J. W. Thompson | year = 1964 | title = Vascular Plants of the Pacific Northwest, Part 2: Salicaceae to Saxifragaceae| pages = 549 | publisher = University of Washington Press}} 7. ^Jepson Manual treatment for Thelypodium howellii subsp. howellii External links
6 : Thelypodium|Endemic flora of the United States|Flora of California|Flora of Nevada|Flora of Oregon|Flora of the Great Basin |
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