Flower:

Tightly packed to loose elongating cluster of white flowers on slender stalks at the top of the plant and arising from some leaf axils in the upper plant. Flowers are about ½ inch across, have 4 white petals with rounded tips, and 6 creamy white to pale yellow stamens in the center. The 4 sepals behind the flower are much shorter than the petals, are pale greenish white around the edges, and turn yellow with age.

Leaves and stems:

There are both basal and stem leaves. Basal leaves are 1 to 2 inches long, oval, round or kidney shaped, hairless, on a stalk usually longer than the leaf blade. The edges may be toothed, scalloped, or toothless, and often wavy.

Stem leaves become less round, proportionately longer and narrower as they ascend the stem, the lower leaves short stalked, upper leaves stalkless and more generally oblong. Edges may be toothless or with a few irregular teeth, and are often wavy. Stems are hairless or sparsely hairy and mostly unbranched except near the flowers.

Fruit:

Fruit is a slender flattened pod about 1 inch long, arranged mostly ascending to erect.

Notes:

Spring Cress, formerly Cardamine rhomboidea, is fairly easy to identify from its roundish, unlobed basal leaves and narrowing stem leaves. The flowers are most similar to Cut-leaf Toothwort (Cardamine concatenata), which has deeply lobed leaves, is a shorter plant, and primarily a woodland species. While Spring Cress is not an uncommon species, unless you like traipsing around mucky seeps and wetlands, it is not so likely to be encountered.