Oenothera

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 (Primula).

Description

The species vary in size from small alpine plants 10 centimeters tall, such as Oenothera caespitosa, to vigorous lowland species growing to 3 meters, such as Oenothera stubbei. 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.

Taxonomy

The classification of the Oenothera has been controversial. The system used here is mainly based on the 1999 classification by Dietrich, Wagner, and Raven. Some species (notably Oenothera caespitosa) are sometimes segregated from Oenothera into other genera, such as Camissonia, but this is not widely accepted.

Uses

Oenothera species are used as food plants by the larvae of some Lepidoptera species. The flower nectar is also a food source for hummingbirds. The seeds of the Oenothera biennis are rich in oil and have been investigated for food and medicinal purposes.

See also

• List of Oenothera species
• Oenothera biennis
• Oenothera caespitosa
• Oenothera stubbei

External links

• Missouri Botanical Garden
• Floridata

Oenothera Resources
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