Annual or biennial herb with a taproot 10 cm - 0.5 m tall Stem: typically single from base, upright, branched in upper third (occasionally near the base), sparsely hairy. Flowers: in dense, branched clusters (raceme), which are borne laterally and terminally on the stems. Racemes numerous, to 10 cm long. Sepals four, greenish white, 1 mm long, cupped. Petals four or none, white, about 2 mm long (equal to nearly twice as long as sepals), bases narrowed. Stamens two. Anthers yellow. Fruit: a pod (silicle), green (turning brownish), 2.5 - 4 mm long, 2 - 3.5 mm wide, widely elliptic to orbicular, flattened, tips notched, tips narrowly winged. Seed one on each side. Lower leaves: reverse lance-shaped, sharp-toothed to pinnately divided or even twice pinnately divided, wilted, sparsely hairy. Upper leaves: alternate, not clasping, deep green, smaller than lower leaves, less than 1 cm wide, linear to reverse lance-shaped, bases narrowing, tips pointed, sometimes toothed, sparsely hairy.
Similar species: Lepidium latifolium is similar but has lance-shaped to narrowly egg-shaped leaves that are sometimes over 1 cm wide. Lepidium densiflorum, which does not have flower petals equal to (or nearly twice as long as) the sepals, can be difficult to distinguish from L. virginicum if not in flower. Lepidium ruderale is foul-smelling. None of the aforementioned Lepidium species have flower petals equal to (or nearly twice as long as) the sepals like L. virginicum does.
Flowering: May to early December
Habitat and ecology: A very common weed that grows in a wide variety of disturbed habitats. Look for it along roads, railroads, and woodland edges. Also grows in fields, gardens, and waste areas.
Occurence in the Chicago region: non-native
Etymology: Lepidium comes from the Greek word lepis, meaning scale, which refers to the shape of the silicles. Virginicum means "of or from Virginia."
Erect annual or biennial 1-5 dm; basal lvs oblanceolate, sharply toothed to pinnatifid or even bipinnatifid; upper lvs smaller, oblanceolate to linear, dentate to entire, acute, narrowed to the base; racemes numerous, to 1 dm; pet equaling to twice as long as the sep; stamens 2; fr broadly elliptic to orbicular, widest at or below the middle, 2.5-4 נ2-3.5 mm, narrowly winged across the tip; style included in the notch; 2n=32. Dry or moist soil, fields, gardens, roadsides, and waste places; Nf. to Fla., w. to the Pacific states. Our plants, with accumbent cotyledons, are var. virginicum.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Annual herb, 15-70 cm tall from a taproot; stems erect, branching above the base, minutely pubescent below and glabrous above. Leaves: Basal leaves petiolate, withering before the plant flowers; stem leaves alternate, sessile or on short petioles; blades 5-15 cm long, obovate, more or less pinnately lobed to dissected, the upper leaves usually not lobed. Flowers: Small and white in terminal racemes, on 2-6 mm pedicels; sepals 4, less than 1 mm long; petals 4 in a cross formation, 1-3 mm long, white. Fruits: Capsules elliptic to orbicular, 2-4 mm wide, glabrous, with a shallow notch at tip, a tiny persistent style within the notch; seeds ovate, 1-2 mm wide. Ecology: Found in dry, generally open areas below 7,500 ft (2286 m); flowers February-August. Distribution: Throughout the US, much of s CAN, and MEX; introduced in S. Amer., Europe, Asia, s Africa, Australia Notes: Lepidium is a genus in the mustard family with distinctive small, round, flat seed pods and small white flowers. L. virginicum can generally be distinguished from other Lepidium spp. by the petals which are usually longer than the sepals. L. densiflorum has rudimentary petals less than 1 mm long, or can have no petals at all. L. lasiocarpum has petals and sepals about the same length, 1 mm long. Ethnobotany: The plants were eaten raw as greens; also used medicinally to treat blisters, tuberculosis, and poison ivy rash. Editor: Sbuckley 2010, AHazelton 2017 Etymology: Lepidium comes from the Greek lepidion, meaning "a little scale," in reference to the flattened shape of the seed pods; virginicum means of or from Virginia.