Mustard evening primrose is an erect glabrous to subglabrous annual with somewhat coarse short branches.  It derives its name from the resemblance to certain mustard plants, especially the four small petals.  The leaves are sparse, mostly in a pinnatifid basal rosette, lanceolate and irregularly cleft, which wither by the time of flowering, and some cauline, smaller, few and far apart, and irregularly toothed.  The flowers are few and widely spaced, solitary on short stems rising from the leaf axils.  The sepals are reflexed when the flower opens, and the four petals are ovate, yellow or orange drying to pink or reddish, sometimes with reddish spots near the base.  There are four long and four short stamens, and a single pistil with a rounded stigma about as long as the longer stamens.  The seed capsules are straight or slightly curved, reflexed sharply at maturity, and contain olive-colored seeds which are often flecked with purple dots and arranged in one row per chamber.  Mustard evening primrose inhabits dry slopes and disturbed areas such as burn sites below 5000' in grassland, chaparral and coastal sage scrub, both in cismontane s. to c. California and occasional at the w. edge of the Mojave Desert, blooming from April to May.  These pictures were taken along the Backbone Trail in the Santa Monica Mts.

Click here for Latin name derivations: 1) Eulobus 2) californicus.
Pronunciation: yoo-LOBE-us ka-li-FOR-ni-kus.
Click here for Botanical Term Meanings.
Formerly Camissonia californica.