Stems (when present) 1-2 dm. Basal leaves: petiole 0.3-2.6 cm; blade 2.3-8.5(-10) cm, lobes 3-10 on each side, margins coarsely dentate, terminal lobe suborbicular, 0.3-0.6 cm × 5-7 mm (slightly shorter than wide), slightly larger than lateral lobes, margins coarsely dentate. Fruiting pedicels: solitary flowers 30-120 mm; racemes to 40 mm. Flowers: sepals widely spreading, oblong, 2.5-4.5 × 0.9-1.5 mm; petals often erect, white, oblanceolate, 3.7-6.4 × 1-2(-2.5) mm, claw white or pale yellow, 1.3-2.5 mm, apex obtuse or truncate; filaments: median 2.5-4.2 mm, lateral 1.6-2.6 mm; anthers 0.5-0.8(-1) mm. Fruits narrowly oblong, (1.5-) 2-3 cm × 3-4(-5) mm, smooth, latiseptate; valves thin; ovules 18-26 per ovary; style 0.9-2(-2.5) mm. Seeds 2.3-3.5 mm diam.; wing 0.2-0.4 mm wide; embryo slightly accumbent. 2n = 30. Flowering Mar-Apr. Rocky ledges, cedar glades, pastures, roadsides, old fields, thin soil on limestone beds, seeps on limestone rubble; 100-500 m; Ala., Ark., Ga., Ind., Ky., Mo., Ohio, Tenn. Leavenworthia michauxii Torrey, which pertains here, is an illegitimate name based on Cardamine uniflora Michaux.
From Flora of Indiana (1940) by Charles C. Deam
This species is known from only one county in the state. It was discovered by Chas. R. Barnes in 1877 at a place locally known as Denny's Lick, about a mile southeast of Charlestown, Clark County. I collected it there in mature fruit, May 1, 1918, and late in May, 1933, some members of the Indiana Academy of Science visited the place and found it abundant over several acres but it was almost past the fruiting stage. The early fruiting dates indicate that it must flower early in April. The habitat is the washed limestone slopes of a permanent pasture where it is associated with Draba verna, Oxalis violacea, and Veronica arvensis.
Principal lvs 2-10 cm נ5-10 mm, deeply pinnatifid with to 9 pairs of acutely toothed lobes, gradually increasing in size from the petiole towards the tip, the terminal lobe only slightly larger than the adjacent lateral pair; sep at first greenish, later purplish; pet white, narrowly lingulate, truncate, usually erect, 5-7 mm, frs thick and somewhat fleshy, 1.5-3 cm נ3-5 mm, nearly as thick as wide, the persistent style 1.5-3 mm; seeds broadly winged, suborbicular, 3-4 mm, the areolae smaller over the embryo than on the wing; radicle strongly bent; 2n=30. Fl before the other spp., and becoming somewhat weedy. Sw. O. to nw. Ga. and nw. Ark.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.