This is one of the few alien species of Brassicaceae in Ky. that has true rhizomes; see also Rorippa sylvestris. Due to this character, its corymbose racemes and its indehiscent fruits, draba and a few close relatives have been generally treated as the genus Cardaria. However, recent research has indicated that these species are nested within the phyologeny of Lepidium, and are relatively close to L. campestre; thus, Lepidium draba L. may become the preferred name again (Y, FNA 7). Although a serious weed in western North America, this species is rare or absent in southeastern states (K, W). The closely related L. chalapense L. (= C. draba ssp. chalepensis) and L. appellianum Al-Shehbaz ( = C. pubescens) may also be expected (Y). These three "hoary-cresses" are noxious weeds that include a complex polyploid series: 2n = 16 (appellianum); 32, 64 (draba); 48-128 (chalepensis).