''Oenothera biennis'', the common evening-primrose,
is a species of flowering plant in the family Onagraceae,
native
Native may refer to:
People
* Jus soli, citizenship by right of birth
* Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory
** Native Americans (disambiguation)
In arts and entert ...
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.
Evening primrose oil is produced from the plant.
[
Other common names include evening star, sundrop, weedy evening primrose, German rampion, hog weed, King's cure-all and fever-plant.][
]
Description
''Oenothera biennis'' has a life span of two years (biennial
Biennial means (an event) lasting for two years or occurring every two years. The related term biennium is used in reference to a period of two years.
In particular, it can refer to:
* Biennial plant, a plant which blooms in its second year and th ...
) growing to tall. The leaves are lanceolate, long and wide, 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 hermaphrodite, 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 yellow, diameter, with four bilobed petals. The flower structure has a bright nectar guide
Nectar guides are markings or patterns seen in flowers of some angiosperm species, that guide pollinators to their rewards. Rewards commonly take the form of nectar, pollen, or both, but various plants produce oil, resins, scents, or waxes. Such ...
pattern, invisible to the naked eye. This pattern is apparent under ultraviolet light and visible to its pollinators
A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains.
Insects are the maj ...
, moths, butterflies, and bees.
The fruit is a capsule long and broad, containing numerous long seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s, released when the capsule splits into four sections at maturity.[Borealforest]
''Oenothera biennis''
[Plants of British Columbia]
''Oenothera biennis''
[Jepson Flora]
''Oenothera biennis''
[Ultraviolet Flowers]
The seeds of the plant are important food for birds, and it is a larval host for both the primrose moth and the white-lined sphinx moth
''Hyles lineata'', also known as the white-lined sphinx, is a moth of the family Sphingidae. They are sometimes known as the hummingbird moth because of their bird-like size (2-3 inch wingspan) and flight patterns.
As caterpillars, they have a ...
.[The Xerces Society (2016), ''Gardening for Butterflies: How You Can Attract and Protect Beautiful, Beneficial Insects'', Timber Press.]
Uses
Over the centuries, Indigenous people
Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...
in North America have used the plant as food and traditional medicine
Traditional medicine (also known as indigenous medicine or folk medicine) comprises medical aspects of traditional knowledge that developed over generations within the folk beliefs of various societies, including indigenous peoples, before the ...
.
The evening primrose was introduced to Europe in the early 17th century
The 17th century lasted from January 1, 1601 ( MDCI), to December 31, 1700 ( MDCC). It falls into the early modern period of Europe and in that continent (whose impact on the world was increasing) was characterized by the Baroque cultural moveme ...
as an ornamental plant in botanical gardens where its flowers are favored for nectar by pollinators and its seeds supply food for other birds.
Food uses
Most of the plant parts are edible, having a taste that is mild. The roots can be eaten raw or cooked like potatoes. The leaves can be eaten raw in salads or cooked like spinach or in soups. Anishinaabe tribes traditionally make tea from the evening primrose leaves for use as a dietary aid and to reduce fatigue.
The flowering stems are preferably used when they are still young in June. They have to be peeled and can then be eaten raw or fried. The flower buds are denoted as a delicacy and can be harvested from June to October.
The seeds have a protein content of about 15%, an oil content of 24%, and contain about 43% cellulose. The proteins are especially rich in the sulphur-containing amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
s, methionine and cysteine, and tryptophan
Tryptophan (symbol Trp or W)
is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic ...
. Gamma-linolenic acid (GLA), and linoleic acid
Linoleic acid (LA) is an organic compound with the formula COOH(CH2)7CH=CHCH2CH=CH(CH2)4CH3. Both alkene groups are ''cis''. It is a fatty acid sometimes denoted 18:2 (n-6) or 18:2 ''cis''-9,12. A linoleate is a salt or ester of this acid.
...
are present. Mainly for these polyunsaturated
In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food.
The term often refers specifically to triglycerides (triple es ...
fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...
s, evening primrose oil is sold as a dietary supplement.
Research
There is not enough clinical evidence to support the use of evening primrose oil as a therapy for any medical condition.[ A Cochrane review concluded that there was no effect of primrose oil on ]eczema
Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...
. The Mayo Clinic stated there was no good evidence that it affected eczema, diabetic neuropathy or premenstrual syndrome.
The American Cancer Society stated that there was little evidence for its effectiveness as an anti-cancer agent, for which it is sometimes promoted, and "neither GLA nor other GLA-rich supplements (such as evening primrose oil) have been convincingly shown to be useful in preventing or treating any other health conditions."
Adverse effects
Evening primrose oil is considered likely as safe in recommended doses.[ It may increase the risk of bleeding, a concern for patients with bleeding disorders or taking drugs that may increase bleeding.][ The Mayo Clinic recommends caution in people with seizure disorders or mania, and by pregnant or breastfeeding women, and publishes a long list of possible side-effects.][ Oral use of evening primrose oil may cause headaches or ]nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...
.[
]
Traditional medicine
The whole plant and especially the leaves are traditionally boiled to tea by Anishinaabe tribes as an energy stimulant and to facilitate weight loss.[ These tribes also use the roots externally as a ]poultice
A poultice, also called a cataplasm, is a soft moist mass, often heated and medicated, that is spread on cloth and placed over the skin to treat an aching, inflamed, or painful part of the body. It can be used on wounds, such as cuts.
'Poultice ...
to treat piles and boils.[ Additionally, they may be chewed and rubbed onto the muscles to improve strength.]
Agricultural practices
The knowledge of agricultural practices in the cultivation of evening primrose is relatively new and only pertain to the commercialized production of evening primrose seed oil. Information of agricultural practices for the production of root vegetable or other plant parts is not known yet.
The evening primrose prefers sunny, and arid places with loamy soil and occurs below above sea level. One important prerequisite is to meet adequate nitrogen requirements. While too high nitrogen levels could lead to a quality and quantity decline of the oil content in the seeds, moderate nitrogen levels lead to increased seed quality and quantity. Because the evening primrose is a light-dependent germinator, it is important that the seeds are not planted too deep into the soil, about deep. The cultivation of evening primrose is thus suitable for no-till farming
No-till farming (also known as zero tillage or direct drilling) is an agricultural technique for growing crops or pasture without disturbing the soil through tillage. No-till farming decreases the amount of soil erosion tillage causes in certai ...
, but the plants require an intense mechanical weed control. The seeds are tiny, about . They need approximately two to three weeks to germinate and are therefore very susceptible to the outgrowth of weeds.
Evening primrose seeds can be sown in the first half of April (spring seeds) or from mid-July to mid-August (autumn seeds). The time of harvest is approximately 75 to 80 days (spring seeds) or 100 days (autumn seeds) after flowering, and clearly influenced by the plant variety, climate conditions, soil fertility and sowing time. The population development and thus seed maturation of the evening primrose is very heterogeneous which is a rather difficult production factor.
There is not much water needed during the vegetation period. A study has shown, that the irrigation with salt water could increase the oil yield and quality in evening primrose seeds. This might be a great opportunity especially in regions with limited water resources. Thus, the evening primrose could be a valuable alternative oil crop in arid regions.
Finally, the cultivation of evening primrose requires a proper field management otherwise the plant can become invasive. If the seeds are used for pharmaceutical purposes it is also important to grow the evening primrose without any pesticides to avoid any chemical residues.
Oenothera biennis Rosette.JPG, Rosette
Nachtkerze mit Samenständen und Blüten.JPG, Flowers and fruit capsules
Primrose_Moth.jpg, Primrose moth ('' Schinia florida'') in flower
Oenothera biennis ENBLA02.jpeg, Habitat, dry and sunny
References
External links
Profile: Yellow Evening-primrose (''Oenothera biennis'')
Photos, Drawings, Text. (''Wild Plants of Winnipeg'' from Nature Manitoba)
{{Authority control
Edible plants
Night-blooming plants
biennis
Flora of North America
Medicinal plants of North America
Plants described in 1753
Taxa named by Carl Linnaeus