This occurs on calcareous glades of disjunct areas within the Ozark Region, southern Interior Low Plateau and southern Ridge-and-Valey, with concentration in Mo. and Ky. (Cr, FNA 21, Y, K; Binns et al. 2002). It is largely restricted to xeric sites with rocky exposure, but there a few records from damper sites, in particular a 1943 coll. from "wet ground... Black Mud Lane" in JEFF (DHL). The extent to which plants can spread onto deeper soils with appropriate disturbance remains uncertain; but grazing or burning during the spring may be damaging (J. Redden, pers. comm.) E. simulata has been included within E. pallida (Nutt.) Nutt., which has a more western and southern range, often on deeper soils. E. simulata differs as follows: rays rose to whitish (versus pink to purple) and ca. 4-7 mm wide (versus 3-4 mm); pollen yellow (versus usually white); 2n = 22 (versus 44). A more western taxon in this complex, E. angustifolia DC., has also been erroneously reported by BA from Ky. (M); it has shorter rays (1.5-4 cm versus 4-9 cm) and narrower leaves on average (mostly 5-25 mm versus 10-40 mm). Despite, McGregor's (1968) establishment of simulata as a species, Binns et al (2002) have treated angustifolia, pallida, simulata and other taxa as varieties of pallida (Binns et al. 2002). However, recent analysis of secondary chemistry has supported McGregor's taxonomy in general (Wu et al. 2009). Both pallida and angustifolia (e.g. along Zilpo Road in BATH) are sometimes planted as "wildflowers" in Ky., then allowing confusion to proceed.