This globally threatened grassland species occurs mostly in midwestern regions (K), but there are also disjunct localities in the Interior Low Plateaus, southern Ridge & Valley and Coastal Plain (Miss., Ala., Ga.), It is threatened, endangered or locally extinct in all states except Mo., where is still "vulnerable" (NS) and probably declining (Y). It often survives along rights-of-way or in other degraded habitats on relatively deep soils, rather than on better remnants of native vegetation on more xeric rocky sites (with less farming history). In Ky. it is currently known from just HARD and HART, but there are old records from at least four other counties; see M and KSNPC for details. Lack of fire appears to be a critical factor allowing declines in this species across its range (Menges & Dolan 1998). Another factor that deserves deeper investigation is the role of herbivory during spring and summer, including past effects of livestock; deer have prevented establishment of plantings in HART (R. Seymour, pers. comm.). The sticky glands on regia appear to catch small insects that might otherwise damage plants, but there is no evidence of digestion (Dienno et al. 2020); further investigation is needed across the genus.