Small weed, up to about 2 feet tall. Stem leaves long, narrow, coarsely toothed, clasping the stem.Basal leaves long, spatula-shaped, usually with a few teeth or lobes near the stalk. Flowers very small, white, with 4 petals, in a cluster at the top of the stem. The flower cluster continues to grow for some time, producing new flowers at the top, while the older flowers become fruits. Fruits are egg-shaped pods, with thin wings around the edges and a small indent at the top. Blooms spring to fall.

Alien weed of waste places and roadsides. Occasional in Wildwood along the bikepath and in the meadows.

Other roadside weedy mustards are possible in the Park, but have not been reported yet. Wild peppergrass (L. virginicum) has very narrow stem leaves, deeply lobed basal leaves and nearly round pods. Field pennycress (Thlaspi arvense) has wider leaves and deeply notched pods. Roadside pennycress (T. alliaceum) is a nasty invasive that has been spreading over the east coast; it has older flowers and pods on very long, drooping stalks.