Description

Key Characters:

Growth Form: Annuals; glabrous or pubescent, trichomes usually simple, sometimes mixed with stalked, forked ones.

Stems: Stems simple or few from base, erect, unbranched or branched distally, (0.2–)0.5–3(–5) dm, pubescent basally, trichomes predominantly simple, glabrous apically.

Roots:

Leaves: Leaves simple. Alternate. Basal leaves obovate, spatulate, ovate, or elliptic, 0.8–3.5(–4.5) cm × (1–)2–10(–15) mm; cauline blade lanceolate, linear, oblong, or elliptic, (0.4–)0.6–1.8(–2.5) cm × 1–6(–10) mm. Upper surface with simple and stalked 1-forked trichomes. Margins of basal leaves entire, repand, or dentate, apex obtuse, adaxial surface with predominantly simple and stalked, 1–forked trichomes; cauline margins usually entire, rarely toothed. Basal leaves short-petiolate; cauline leaves subsessile. Stipules absent.

Flowers: Flowers in racemes (few- to several-flowered), not elongated in fruit. fruiting pedicels ascending, divaricate, or slightly reflexed, slender. Flowers bisexual (perfect). Fruiting pedicels divaricate, 3–10(–15) mm. Calyx of 4 sepals; sepals 1–2(–2.5) mm, lateral pair not saccate basally, (glabrous or sparsely pubescent distally, trichomes simple). Corolla of 4 petals; petals white, spatulate, 2–3.5(–4) × 0.5–1.5 mm, (base attenuate to claw). Stamens 6; filaments 1.5–2 mm. Ovary superior; ovules 40–70 per ovary; style to 0.5 mm.

Fruit: Fruit cylindric or linear; smooth; terete (cylindrical); (0.8–)1–1.5(–1.8) cm × 0.5–0.8 mm; valves each with distinct midvein. Seeds light brown; (plump); ellipsoid 0.3–0.5 mm; cotyledons incumbent.

Ploidy: 2n = 10

Habitat: Sandy areas along roadsides; stream banks; railroad tracks and embankments; open pastures; grassy flats; fields; prairies; floodplains; woods; lawns; limestone ledges and crevices; bluffs; shale and serpentine barrens; gravel; sandstone.

Elevation Range: 0–1,000 m.