Washington County's Endangered Plants


Arctomecon humilis
Dwarf (or Low) bearclaw poppy
Federally listed species since 1979
Lives only in Washington County, Utah
Poppy family

Primary threats: Urban expansion (residential and commercial development, highway projects completed and proposed leading to direct habitat loss, loss of pollinators and habitat fragmentation) and off road vehicles
Recent/impending impacts: Sun River expansion destroyed plants/habitat in May 2004, Atkinville interchange, Southern Corridor, further Sun River expansion, SITLA actions on White Dome and particularly the road that SITLA plans to build directly through its habitat destroying more plants and fragmenting its habitat further, massive residential development in or near almost of its remaining range, significant ongoing damage by OHV's
Learn more about the conservation history of this species
Arctomecon humilis 5/3/04 Tony Frates
Arctomecon humilis
Astragalus ampullarioides
Shivwits (or Shem) milkvetch
Federally listed species since 2001
Lives only in Washington County, Utah
Pea family

Primary threats: Urban expansion (see above) and invasive species
Astragalus ampullarioides 5/2/04 Tony Frates
Astragalus ampullarioides


Astragalus holmgreniorum
Holmgren's (or Paradox) milkvetch
Federally listed species since 2001
Lives primarily in Washington County, Utah
(a few plants occur just barely over the UT-AZ border)
Pea family

Primary threats: Urban expansion (see above), off road vehicles and invasive species
Impending impacts: Atkinville interchange, Southern Corridor, Sun River expansion, massive residential and other development planned by SITLA in its largest extant population
This plant species may currently be the most endangered of becoming extinct in Utah.
Astragalus holmgreniorum 5/2/04 Tony Frates
Astragalus holmgreniorum


Pediocactus sileri
Siler (or Gypsum) cactus
Federally listed species since 1979 (reclassified in 1993)
Lives only in Washington and Kane Cos. in Utah
(also occurs in northwestern Arizona)
Cactus family

Primary threats: Urban expansion, off road vehicle use, cattle grazing and cactus poaching
Impending impacts: Southern Corridor, SITLA actions on White Dome, motorcyle/ATV events
Pediocactus sileri 5/3/04 Tony Frates
Pediocactus sileri


Petalonyx parryi
Parry's petalonyx
Rare plant species
In Utah, only lives in Washington County
(also occurs in Nevada and Arizona)
Blazing star (or Stickleaf) family

Primary threats: Urban expansion (the plant pictured was destroyed by residential development shortly after being photographed in 2004)
Recent/impending impacts: Silver Falls/KLC Properties residential development resulted in the destruction of plants/habitat in May 2004 and other residential development near the town of Washington (Washington Fields); Southern Corridor, SITLA actions on White Dome
Petalonyx parryi 5/3/04 Tony Frates
Petalonyx parryi