Northern Prairie Wildlife Research Center
Western Wetland Flora
Field Office Guide to Plant Species
Oenothera elata HBK.
- Family: Evening-primrose (Onagraceae)
- Flowering: June-September
- Field Marks: The distinguishing features of this evening-primrose are the 4-parted stigmas, the yellow petals 1-2 inches long, and the narrow leaves less than 1/4 as wide as long.
- Habitat: Along streams, in marshes, on wet cliffs.
- Habit: Biennial herb with a taproot.
- Stems: Upright, branched, up to 6 feet tall, hairy, with some of the hairs gland-tipped.
- Leaves: Alternate as well as clustered at the base of the plant, simple, elliptic to lanceolate, usually pointed at the tip, hairy, the basal leaves often coarsely toothed, up to 7 inches long, the leaves on the stem finely toothed, up to 4 inch
- Flowers: Many crowded in a dense showy cluster up to 15 inches long; bracts lanceolate, hairy.
- Sepals: 4, green to reddish, united below to form a floral tube, the tube up to 1 3/4 inches long, the lobes up to 1 3/4 inches long, hairy.
- Petals: 4, yellow but fading to reddish, free from each other, obovate, up to 2 inches long.
- Stamens: 8, up to 1 1/2 inches long.
- Pistils: Ovary inferior, hairy.
- Fruits: Capsules cylindrical, up to 2 inches long, up to 1/4 inch thick, hairy containing several reddish brown seeds.
- Notes: In the past this species has been known as O. hookeri.
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