Northern Prairie Wildlife Research Center
Common Evening Primrose (Oenothera biennis)
- Family: Evening Primrose (Onagraceae)
- Flowering: June-October.
- Field Marks: Common evening primrose lacks a 4-sided
ovary and capsule, has angular seeds, and calyx lobes adhering to
- Habitat: Old fields, roadside ditches.
- Habit: Coarse perennial herb with a taproot.
- Stems: Erect, branched, hairy, up to 5 feet tall.
- Leaves: Alternate, simple, lanceolate to oblong,
pointed at the tip, tapering to the base, with or without small
teeth, hairy, up to 6 inches long, up to 2 inches broad.
- Flowers: Several in terminal clusters, yellow, up to
2 inches across.
- Sepals: 4, green, hairy, usually adhering to each
other and forming a long tube.
- Petals: 4, free, yellow, up to 1 1/4 inches long,
opening in the evening.
- Stamens: 8.
- Pistils: Ovary inferior; stigmas 4.
- Fruits: Capsules cylindrical, not winged, usually
hairy, up to 2 inches long; seeds reddish, 1/12-1/10 inch long.
- Notes: Roots and leaves of the young plants are eaten
by wildlife and may be eaten by humans.
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