Oenothera biennis, a
biennial herb originating in North America, grows wild on roadsides,
wastelands, or riversides. Stems branch well at lower portions and
rise to 0.5-1.5m, with hairs facing upward. Leaves are in a
long-oblong-like lanceolate, with sharp tips and shallow serrations
on the margins. Flowers, yellow, measure 2-5cm in diameter. Capsules
are cylindrical, 2-3cm in length. Bloom time: June-September.