Oenothera wolfii

Common Names:
Wolf's evening-primrose
(Munz) Raven, Dietrich & Stubbe
Growth Habit:
CPC Number:
Profile Contributors:
Edward Guerrant, Ph.D.
Fully Sponsored

Reference Links

ITIS - Tropicos - USDA Plants - Fish & WildLife

Participating Institutions

The following Participating Institutions are custodians for this species in the CPC National Collection:
Rae Selling Berry Seed Bank & Plant Conservation Programs

The conservation of Oenothera wolfii is fully sponsored.
Edward Guerrant, Ph.D. contributed to this Plant Profile.


Of all the many ways to be driven to extinction, Wolf's evening primrose is under assault from one of the most insidious and bizarre; its own offspring! We believe that children are a blessing. We believe that genetic diversity and the mixing of genomes is a good thing. In the botanical world, these assumptions aren't always true.
Oenothera wolfii grows along the coast of Oregon and northern California. It has been found growing in cracks in a parking lot, along the upper strand of the beach, on bluffs above the ocean, and along roadsides; all areas subject to a moderate amount of disturbance especially from sea spray and blowing sand. It exhibits many characteristics typical of an "opportunist" species such as high germination rates and low seedling survival. According to a local botanist, Oenothera wolfii "is as easy to grow as any I've seen, which makes one wonder why it is so rare" (Stansell 1989).

So, what makes this plant rare Its peculiar habitat limits it to specific sites along the coast. It is found mostly on discontinuous patches of Cenozoic-era marine deposits, which are isolated from each other by other sedimentary and metamorphic rock. This may explain the disjunct distribution of the species. Within these sites, it requires well-drained soils with adequate moisture, minimal competition and protection from northwesterly exposure. The infrequency of sites that match these conditions may contribute to its rarity.

Rarity, in and of itself, is not necessarily of great conservation concern. What is of concern, however, are the multitude of threats to this species. This rare plant is, like so many other species, threatened by loss of habitat due to urban expansion and road paving, and from direct damage to plants by construction and herbicide spraying. Competition from non-native plants is also a problem. The threat from its own offspring is the most damaging and worrisome. Perhaps the most serious and most worrisome threat is from its own offspring.

The ornamental species Oenothera glazioviana originated in Europe, apparently as a stabilized hybrid between two North American species brought to Europe for ornamental purposes. It has been spreading around the globe, not only as a garden plant, but also as a weed. Oenothera glazioviana has become naturalized on every continent except Antarctica. Oenothera glazioviana is an out-breeder and is able to accept pollen from O. wolfii, thus producing viable hybrid offspring. Oenothera wolfii is an inbreeding species and apparently cannot accept pollen from other species. However, O. wolfii has been found to be receptive to pollen from the hybrids, and introgression, or the infiltration of one species' genes into another, is occurring. The genetic integrity of Wolf's evening primrose throughout much of the range in California is questionable (Imper 1997). Scientists are concerned that all O. wolfii genotypes will be diluted by the influence of O. glazioviana and this unique species will vanish from existence.

Why bother maintaining the genetic integrity of this species As a part of a natural ecosystem, Oenothera wolfii plays an important ecological role. We may not fully understand the full impact of its value and its relationship to other species until it is gone. This species may also prove to be useful to humans, and if we allow it to become extinct, we may never know the benefits (see the ecology section for more).

Distribution & Occurrence


Conservation, Ecology & Research