Flower:

Elongating clusters of stalked flowers at the top of the plant and at the tips of branching stems arising from the upper leaf axils, with a densely packed, rounded cluster of open flowers at the tip and fruit forming below.

Flowers are tiny, less than 1/8 inch across, with 4 white, paddle-shaped petals alternating with 4 oblong-elliptic sepals that are light green with thin, whitish edging and have a few hairs on the outer surface. Petals are about twice as long as the sepals but occasionally petals are absent altogether. In the center are 2 yellow-tipped stamens and a stubby, white style at the tip of a green ovary. Flower stalks are minutely hairy, the hairs cylindric and mostly curved.

Leaves and stems:

Leaves are in a basal rosette as well as alternate all along the stem. Basal leaves are long stalked, spatula shaped to pinnately lobed and wilt away early. Lower stem leaves are irregularly toothed or lobed, 1 to 4 inches long, up to 1 inch wide, widest above the middle, tapering to a stalk at the base.

Leaves usually become more linear, less toothy, and stalkless as they ascend the stem. Surfaces are minutely hairy. Stems are erect, usually branched in the upper third, and also minutely hairy. Stem and leaf hairs are cylindric and mostly curved.

Fruit:

Fruit is a flat pod, round in outline, usually slightly wider than long, widest near the middle, up to about 1/6 inch (4mm) long with a small notch at the tip. It dries to a papery brown shell and splits down the middle when mature.

Each side of the pod contains a single seed. Inside the seed, the pair of seed leaves (cotyledons) are parallel to each other but perpendicular to the embryo, as viewed in cross-section.

Notes:

Virginia Peppergrass has not often been recorded in Minnesota but is likely under-reported, probably often mistaken for the more ubiquitous Green-flowered Peppergrass (Lepidium densiflorum). There are 3 key differences: L. densiflorum flower petals are shorter than the sepals but more typically absent altogether; stem and stalk hairs are cylindric to club-shaped and mostly straight (magnification required to see); inside the seed, the pair of seed leaves (cotyledons) and embryo are all parallel to each other, in a single row as viewed in cross-section (magnification also required). While most references note the shape of the fruit is also diagnostic, specifically whether it is widest at or above the middle, this is too subtle a difference to be consistently reliable.

There are two recognized subspecies of L. virginicum: subsp. menziesii is a western species with flattened fruit stalks and cotyledons lined up with the embryo in a single row; subsp. virginicum, present in much of North America including Minnesota, has round fruit stalks and cotyledons perpendicular to the embryo (see photo below). There are also several non-native Lepidium species that are similar to L. virginicum, but they are either not present in Minnesota, though may be in neighboring states, or are very rarely encountered here. The mid to upper stem leaves can easily distinguish L. virginicum from these others, which may have leaf stalks, lobes (auricles) at the leaf base, or clasping bases, while L. virginicum stem leaves are stalkless, not clasping, and lack any basal lobes.