Physaria filiformis

Known from the limestone glades of the Springfield Plateau area of southwestern Missouri and from parts of Arkansas. The species is currently known from about 60 sites (in 1987, when the species was listed endangered, only 9 sites where known); further inventories may continue to uncover additional populations. Population sizes fluctuate greatly, but may reach half a million in the most favorable years. Populations may face significant threats from exotic plant species, especially Bromus tectorum, and from fire suppression and subsequent woody plant encroachment. Some populations are protected and managed with prescribed fire and woody plant removal. However, some populations and much of the species' habitat could be impacted by urban/suburban expansion.

Endemic to limestone glades of the Springfield Plateau area of southwest Missouri in Dade, Greene, Lawrence and Christian cos. Also in 2 counties in AR.

59 locations, 6 on MO highway rights-of-way, 45 on private land, 2 within Wilson's Creek National Battlefield, 3 on TNC lands, and 3 on MDC lands.

About half the known sites are considered to be high quality and several large populations are well protected, including active management with prescribed burns (McKinzie 2003). However, some populations and potential habitat faces urban/suburban expansion. The species is compatible with light grazing/disturbance, but in undisturbed areas may be shaded out by woody plant encroachment. Exotic plants, especially Bromus tectorum can be a major threat. Active management, especially prescribed burns, greatly reduces threats.