There seems to be more discussion in the literature about the scientific name for tansyleaf evening primrose than there is about the wildflower itself. There are three accepted scientific names for this beautiful yellow flower – Taraxia tenecetifolia, Camissonia tenecetifolia and Oenothera tenecetifolia. Currently Taraxia appears to be the favored genus. Tansyleaf sun cup is another common name for this evening primrose.
A native perennial found in Washington, Oregon, California, Nevada, Idaho and Montana, tansyleaf evening primrose grows from a woody taproot and spreads by lateral shoots. The leaves are narrowly lance-like and lined with deep irregular lobes and are arranged in a flat rosette with a central inflorescence. The showy, solitary flowers have four petals and sepals that are swept backwards. The stigma atop the elongated style of the inferior ovary (female reproductive organ) is a rounded head. Each of the eight stamens (male reproductive structures) have pollen enmeshed to the anther in cobwebby threads (viscin threads). Two rows of tansyleaf evening primrose seeds are contained in leathery capsules.
Insects, particularly bees, consume the nectar of tansyleaf evening primrose.
These tansyleaf evening primrose plants were growing along the Eagle Lake (Shasta County CA) bike trail.