Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California, also in scattered locations in other parts of the central and southern U.S.
Habitat: Open, disturbed areas at low elevations.
Origin: Introduced from Europe
Growth Duration: Annual
Conservation Status: Not of concern
Taprooted annual, the stems ascending to erect, usually simple.
Leaves opposite, the cauline sessile, the basal sometimes petiolate; blade 1-veined, linear to linear-lanceolate, acute, not succulent.
Inflorescences terminal, of 1-3 flowers, or flowers single in the leaf axils, subtended by a pair of leaf-like bracts; pedicles erect; sepals 4, distinct, green, lanceolate, 4-7 mm. long, the margins white; petals 4, white, not clawed or notched; stamens 4, inserted at base of superior ovary; styles 4, filiform, about 1 mm. long.
Capsules cylindric, opening by 8 teeth, about as long as the sepals.