CPC Plant Profile: Antioch Dunes Evening-primrose
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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
Description
  • Global Rank: T1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Onagraceae
  • State: CA
  • Nature Serve ID: 143664
  • Date Inducted in National Collection: 03/06/1993

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).

Participating Institutions
Updates
  • 09/01/2020
  • Orthodox Seed Banking

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
  • Orthodox Seed Banking

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
  • Seed Collection

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.

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Photos
Nomenclature
Taxon Oenothera deltoides ssp. howellii
Authority (Munz) W. Klein
Family Onagraceae
CPC Number 2995
ITIS 27392
USDA OEDEH
Common Names Antioch Dunes Evening-Primrose | Antioch Dunes evening primrose [
Associated Scientific Names Oenothera deltoides var. howellii
Distribution This species is endemic to Contra Costa County in California (USFWS 1984).
State Rank
State State Rank
California S1
Habitat

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

Ecological Relationships

Hawkmoths pollinate this species and a study by Pavlik et al. (1993) recorded their visits in very low numbers affecting seed set of the plant. The seed bank of this species was found to be lower than other species in the Antioch Dunes, which makes it potentially more susceptible to any threat (Pavlik et al. 1993).

This species responds positively to fire (USFWS 2008).

Pollinators
Common Name Name in Text Association Type Source InteractionID

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