Although this cosmopolitan winter-annual has been common in Ky. for more than a century (Gray 1864; Gm), it was not recorded before the Civil War; see Short's note under "Cardamine virginica" (Planodes). Rather like C. hirsuta, D. verna is rare or absent in colder and drier regions of North America, but it has spread more into the northern interior (PL). Although many self-pollinating races with different chromosome numbers (2n = 14 to 64) have been described in Europe since Linnaeus, there has been little attempt to distinguish any of these in North America (Al-Shehbaz 1987, FNA 7; but see St). Flowering in Ky. occurs mostly during Mar-Apr, but often as early as mid-Feb (as in Holosteum, which can associate).