Common eveningprimrose
June 5, 2015
Oenothera biennis L. Onagraceae (Eveningprimrose family)
Life cycle
Usually an erect biennial or winter annual. Occasionally a summer annual.
Common eveningprimrose plant.
Leaves
Alternate, narrow oval with smooth to slightly wavy leaf margins and distinctive pink to white midveins. Leaves initially develop from a basal rosette.
Common eveningprimrose rosette.
Stems
Erect, semi-woody, approaching 5 feet in height. Stem usually branches only at the top and may be visible through the winter.
Common eveningprimrose flowering stem.
Flowers and fruit
Flowers are yellow, attached to fused sepals forming a tube and found in terminal spikes. Seed capsules are woody, cylinder-shaped and thickest near the bottom.
Reproduction
Seeds.
Similar weeds
Cutleaf eveningprimrose (O. laciniata Hill) Differs by having a prostrate to moderately erect, branching stem; wavy and coarsely toothed leaves; yellow to reddish flowers in the upper and middle leaf axils; and linear, cylinder-shaped seed capsules.
Cutleaf eveningprimrose leaf is coarsely toothed.
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