Washington County's Endangered Plants

Endangered Plants of Washington County

Arctomecon humilis
Astragalus ampullarioides
Astragalus holmgreniorum
Pediocactus sileri
Petalonyx parryi
Sphaeralcea gierischii

Arctomecon humilis

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

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

Arctomecon humilis juvenile

Astragalus ampullarioides

Shivwits (or Shem) milkvetch
Federally listed species since 2001
Occurs only in Washington County, Utah
Pea family, Fabaceae

Primary threats: Urban expansion (see above) and invasive species

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, Fabaceae

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

Pediocactus sileri

Siler's Pincushion (or Gypsum) cactus
Federally listed species since 1979 (reclassified in 1993)
In Utah, occurs only in Washington and Kane Counties, Utah
(also occurs in northwestern Arizona)
Cactus family, Cactaceae

Primary threats: Urban expansion, off road vehicle use, cattle grazing, cactus poaching and gypsum mining.

Impending impacts: Southern Corridor, SITLA actions on White Dome, motorcyle/ATV events.

Very slow growing and very prone to impacts; juvenile plants seem to be missing in a number of populations. These plants and the biologic crusts upon which they depend need to be left undisturbed.

Pediocactus sileri

Petalonyx parryi

Parry's Sandpaper Plant
Rare plant species (shrub)
In Utah, only occurs in Washington County
(also occurs in Nevada and Arizona)
Blazing star (or Stickleaf) family, Loasaceae

Primary threats: Urban expansion (the plant pictured to right/top was destroyed by residential development shortly after being photographed in 2004); gypsum mining.

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.

This plant requires gypsipherous soil. An historic St. George population from which it was first collected by Dr. Charles C. Parry no longer exists.

Petalonyx parryi

Sphaeralcea gierischii

Gierisch's globemallow
Federal candidate species as of Dec. 10, 2008
In Utah, occurs only at extreme southern edge of Washington County
Only one population was found in Utah
Also occurs in adjacent Mohave County, Arizona
Mallow family, Malvaceae

Primary threats: Gypsum mining, off road vehicles and other recreational impacts

Recent/impending impacts: the growth of Sun River, the new St. George airport and ever increasing local human populations place the lone Utah occurrence at ever increasing peril.

All Utah-Arizona occurences are located within roughly a 10 square mile area; total occupied habitat is less than 60 acres.

Sphaeralcea gierischii