This generally diploid species (2n = 20) is widespread on dry acid soils across southeastern states east of the Mississippi Rv. (K); it is also locally common in La. but rare and disjunct (or perhaps adventive) in Ark. and Mo. (Ladd & Thomas 2015; Thomas 2017). All plants in Ky. probably match var. glandulosum (Michx.) DC. but that segregate may not be worth recognizing (see also W). The more southern var. album (sometimes misnamed "E. petaloideum Britt."), with less glandular involucres, has been reported but does not appear to occur in Ky. (M). A few colls. may be hybridized with torreyanum (HART at TENN, MCRE at KY), sessilifolium or other species; see also notes under vaseyi.