Search / Plant Profile / Oenothera deltoides ssp. howellii

Plant Profile

Antioch Dunes Evening-primrose (Oenothera deltoides ssp. howellii)

This shot shows several of the white flowers of this Antioch Dunes evening primrose. Photo Credit: Dieter Wilken

Global Rank: T1 - Critically Imperiled
Legal Status: Federally Endangered
Family: Onagraceae
State: CA
Nature Serve ID: 143664
Lifeform: Forb/herb
Date Inducted in National Collection: 03/06/1993

Description:

In 1984, a humpback whale beached itself on the dunes in the Antioch Dunes National Wildlife Refuge. Thousands of people came to see the animal, using the dunes to get the best view and, unfortunately, killing a number of endangered plant species growing there by trampling them to death. Fortunately for the Antioch Dunes evening primrose, however, the human-caused disturbance actually allowed it to flourish. This evening primrose is a many-branched perennial herb that produces showy, white flowers from March to September and has grayish toothed or divided leaves. Because of its beauty, this primrose was chosen to be one of four endangered plants to be depicted in a set of stamps issued in 1979 (USFWS 1984, Rogers 2015).

Where is Antioch Dunes Evening-primrose (Oenothera deltoides ssp. howellii) located in the wild?

Habitat:

This endangered taxon grows on loose sand and stabilized dunes (USFWS 1984).

Distribution:

This species is endemic to Contra Costa County in California (USFWS 1984).

States & Provinces:

Antioch Dunes Evening-primrose can be found in California

Which CPC Partners conserve Antioch Dunes Evening-primrose (Oenothera deltoides ssp. howellii)?

Regional Parks Botanic Garden

Not Sponsored

Assigned 06/09/17

California Botanic Garden

Not Sponsored

Conservation Actions

Assigned 06/09/17

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

09/01/2020

Based on an September 2020 extract of the California Plant Rescue Database, University of California Botanical Garden holds 1 accessions of Oenothera deltoides subsp. howellii in orthodox seed collection. We are uncertain as to how many total seeds are in this collection.

09/01/2020

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 25 accessions of Oenothera deltoides subsp. howellii in orthodox seed collection. There are as many as 442866 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

08/05/2020

Based on an August 2020 extract of the California Plant Rescue Database, University of California Botanical Garden has collected 1 seed accessions of Oenothera deltoides subsp. howellii from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass an unknown number of maternal plants

Nature Serve Biotics

05/02/2017

Endemic to California's Antioch Dunes, Oenothera deltoides ssp. howellii is known only from three native occurrences in Contra Costa County. Recovery work is in progress and two occurrences have been introduced in Sacramento and Contra Costa County. The plant is seriously threatened by mining, agriculture, industrial development, and non-native plants.

01/01/2010

Industrial development Sand mining Agricultural conversion Fire control activities Off-road vehicles (ORV's) Exotic invasives (NatureServe 2001)

01/01/2010

Seven sites in the 70 acres along the San Joaquin River near Antioch, Contra Costa Co. Only three of these are naturally occurring populations--the other four are reintroduced populations. (Skinner 1997; NatureServe 2001)

01/01/2010

Pavlik et al. studied the population biology of this species (Pavlik et al. 1988, 1993; Pavlik 1994) A graduate student in Claremont Graduate School (Julie A. Greene) studied the reproductive ecology of this species (Greene 1995).

01/01/2010

Recovery work is in progress and two occurrences have been introduced in Sacramento and Contra Costa County. (CDFG 2002)

01/01/2010

The Antioch Dunes need to remain protected from activities that would degrade the habitat, and management activities should continue to enhance both endangered plant species that occur on the dunes (Oenothera deltoides ssp. howellii and Erysimum capitatum var. angustatum).

01/01/2010

Maintain a genetically representative seed bank.