Oenothera cinerea cinerea

Description

Oenothera is a genus of about 145 species of herbaceous flowering plants native to the Americas. It is the type genus of the family Onagraceae. Common names include evening primrose, suncups, and sundrops. They are not closely related to the true primroses (genus Primula). The species vary in size from small alpine plants 10 centimeters tall, such as O. acaulis from Chile, to vigorous lowland species growing to 3 meters, such as O. stubbei from Mexico. The leaves form a basal rosette at ground level and spiral up to the flowering stems. The blades are dentate or deeply lobed (pinnatifid). The flowers of many species open in the evening, hence the name "evening primrose". They may open in under a minute. Most species have yellow flowers, but some have white, purple, pink, or red. Most native desert species are white. Oenothera caespitosa, a species of western North America, produces white flowers that turn pink with age. One of the most distinctive features of the flower is the stigma, which has four branches in an X shape. Certain Oenothera plants have edible parts. The roots of O. biennis are reportedly edible in young plants. Primrose is commonly sold as a dietary supplement in capsules containing the seed oil, and is advertised to treat various medical disorders, such as eczema, diabetic neuropathy, rheumatoid arthritis, or numerous other conditions. The main phytochemical in primrose seed oil is gamma-linolenic acid. There is no high-quality scientific evidence that primrose or primrose oil has any effect on human diseases or promotion of health, and specifically no evidence that it is effective to treat eczema or cancer. Most research indicates that orally-administered evening primrose oil does not relieve symptoms of premenstrual syndrome, neither does orally administered primrose oil seem to have any effect in shortening the length of pregnancy or labour. Consuming primrose oil may cause headache or stomach upset, may increase the risk of complications during pregnancy, and may increase the risk of bleeding in people given prescription drugs as anticoagulants, such as warfarin.