Camissonia tanacetifolia ssp. tanacetifolia
Synonym: Oenothera tanacetifolia
Tansy leaf evening primrose along the road to Blue Sky, Hart Mt. National Antelope Refuge.........7/5/96.
Tansy leaf evening primrose is a low growing, somewhat weedy perennial with a rosette of basal leaves and a tuft of central flowers. It lacks stems. The leaves are 5-20 cm long and 1-3.5 cm wide. The blades range from narrowly to broadly lanceolate or oblanceolate with sinnuate-pinnatfid margins. The slender petioles range from 1/2 to nearly as long as the blades. The leaves are covered with dense, short hairs which give a bluish cast to the leaves.
The 4 petals are yellow in color, aging to purplish and range from 10-16 mm long with rounded to blunt tips. The stamens are unequal in length, withthe longest about 1/2 the length of the petals. The style is about as long as the petals and the stigma as seen in the photo at right is globose.
Tansy leaf evening primrose may be found in moist soil (which dries later in the season) in meadows, swales, roadsides, and along riverbanks in the sagebrush plains or in ponderosa pine forests.
Tansy leaf evening primrose may be found to the east of the Cascades from Washington south to Sierran California and east to Idaho and Montana.
In the Columbia River Gorge, it may be found along the Columbia River near the mouth of the Deschutes River.