This is a relatively uniform diploid (2n = 34) typical of native grasslands on deep well drained soils of east-central states, especially from the Miwest to the Gulf Coastal Plain (K). East of the Appalachians, the species is also widely scattered but generally onsidered adventive (F, W). The species may be relatively close to occidentalis and perhaps the "southeastern perennial clade" (with Angustifolii and Atrorubentes), but its ancestry remains somewhat obscure (Stepherns et al. 2015)*. There may be rare hybrids with occidentalis (= X cinereus Torr. & Gray), giganteus (?= X doronicoides Lam.) and perhaps hirsutus (Cranfill 1992); see M for records of these hybrids from Ky. H. mollis can form large dense stands, and its competitive ability has been linked with allelopathy (Anderson et al. 1978). However, flowering stem tops are often killed by stem boring insects (including moths, Papaipema spp., and perhaps the weevil, Cylindrocopturus adspersus), which prevent seed production (Thomassie et al. 2012; D. Dourson & R. Seymour, pers. comm.). ,<*"The current phylogeny supports three major clades including a large annual clade, a southeastern perennial clade, and another clade of primarily large-statured perennials. Relationships among taxa are more consistent with early phylogenies of the genus using morphological and crossing data than recent efforts using single genes, which highlight the diffi culties of phylogenetic estimation in genera known for reticulate evolution. Additionally, confl ict and low support at the base of the perennial clades may suggest a rapid radiation and/or ancient introgression within the genus.">