This taxon is a fertile tetraploid (2n = 168) derived from crossing of bulbifera and protrusa (Haufler et al. 1990; FNA 2). Several records mapped here remain uncertain. Although most authorities consider treat these plants as a species, there is considerable variation, perhaps reflecting different original hybridizations (see also: Cranfill 1980; Cr, W). Some Ky. plants appear relatively close to protrusa, while others appear closer to bulbifera. Also, tennesseensis can form occasional hybrids with its parent species and with tenuis.