Oenothera deltoides subsp. howellii

Antioch dunes evening-primrose, Antioch Dunes Evening-Primrose

Family: Onagraceae · Type: perennial · Native

Conservation status: CNPS 1B.1 · Endangered

Antioch dunes evening-primrose is a rare (CNPS 1B.1) California native perennial found in the Deltaic Sacramento-San Joaquin Valley region in Contra Costa County, specifically around Antioch, on sandy bluffs and dunes at elevations below 100 meters. Flowering from March to September, this plant produces large pale yellow flowers with delicate petals 20 to 40 millimeters long. Growing with gray-green stems 4 to 8 decimeters tall and branched throughout, it displays a distinctively sprawling habit with spreading wavy hairs. Its leaves are particularly distinctive, with distal leaves featuring wavy lobes and a grayish-green coloration. The fruit develops with a base 3 to 4 millimeters wide, contributing to this unique dune-dwelling plant's adaptation to its specialized habitat.

Habitat: Sandy bluffs, dunes

Bloom period: Mar-Sep

Elevation: < 100 m

Bioregions: Deltaic GV (Antioch, Contra Costa Co.).

California counties: Contra Costa

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.