The Antioch Dunes Evening Primrose, Oenothera deltoides ssp. howellii, is a short-lived perennial plant in the evening-primrose family (Onagraceae). It has large, white flowers that bloom from March to September. Natural stands of the Antioch Dunes evening primrose are found only on the riverine dune habitat located on and immediately adjacent to the Antioch Dunes National Wildlife Refuge.
Antioch Dunes Evening Primrose
From 1984 to 1991, the total population of the Antioch Dunes evening primrose was estimated to range from 4,300 to 5,800 plants. Population numbers fluctuate annually, but the long term trend is clearly declining. The current population numbers for 2011 are estimated to be 1146 individuals. The species and its critical habitats have been protected by the Endangered Species act since 1978.