Flower:

Elongating clusters of stalked flowers at the top of the plant and the end of branching stems arising from leaf axils in the upper plant. Flowers are 1/8 to ¼ inch across with 4 rounded white petals and 6 creamy white to pale yellow stamens slightly protruding from the center. The 4 sepals behind the flower are oblong and hairless, green but may be purplish at the tip.

Leaves and stems:

Leaves are compound, a leaf up to 4 inches long and 1¼ inch wide. Basal and lower stem leaves are similar, with oval to round leaflets that may have a few teeth or shallow lobes, the end leaflet largest. Basal leaves typically wither away by flowering time.

Upper stem leaflets become more narrow, mostly toothless or with a few shallow lobes, with the end leaflet distinctly broader and longer than the lateral leaflets. Stems are often very leafy, mostly hairless or sparsely hairy especially near the base of the plant, green or sometimes purplish.

Fruit:

Fruit is a slender pod ¾ to 1¼ inch long, erect to slightly spreading and mostly straight.

Notes:

A similar species is Small-flowered Bittercress (Cardamine parviflora), which is a smaller, more spindly plant found in dry soil, where Pennsylvania Bittercress is found in moist to wet places. The end leaflet of Pennsylvania Bittercress is also distinctly larger than the lateral leaflets, where they are nearly the same size on Small-flowered Bittercress.