| Oenothera biennis | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Magnoliophyta |
| (unranked): | Eudicots |
| Order: | Myrtales |
| Family: | Onagraceae |
| Genus: | Oenothera |
| Species: | O. biennis |
| Binomial name | |
| Oenothera biennis L. |
|
Oenothera biennis (Common evening primrose or Evening star) is a species of Oenothera native to eastern and central North America, from Newfoundland west to Alberta, southeast to Florida, and southwest to Texas, and widely naturalized elsewhere in temperate and subtropical regions.[1]
Contents |
Oenorthera biennis has a life span of two years (biennial) growing to 30–150 cm tall. The leaves are lanceolate, 5–20 cm long and 1–2.5 cm broad, produced in a tight rosette the first year, and spirally on a stem the second year.
Blooming lasts from late spring to late summer. The flowers are produced on a tall spike and only last until the following noon. They open visibly fast every evening producing an interesting spectacle, hence the name "evening primrose."
The blooms are pale yellow, 2.5–5 cm diameter, with four petals and hermaphrodite. The flower structure has an invisible to the naked eye bright nectar guide pattern. This pattern is apparent under ultraviolet light and visible to its pollinators, moths, butterflies and bees.
The fruit is a capsule 2–4 cm long and 4–6 mm broad, containing numerous 1–2 mm long seeds, released when the capsule splits into four sections at maturity. [2][3][4][5]
It is also known as Weedy evening-primrose, German rampion, hog weed, King's cure-all, and fever-plant.[6]
The mature seeds contain approximately 7–10% gamma-linolenic acid, an essential fatty acid. The O. biennis seed oil is used to reduce the pains of premenstrual stress syndrome and is beneficial to the skin of the face. Also, poultices containing O. biennis were at one time used to ease bruises and speed wound healing .
Its leaves are edible and traditionally were used as a leaf vegetable.[7]