Oenothera biennis (Yellow Evening Primrose) - photos and description
General: Erect, stout stemmed biennial. Plant stems are sparsely hairy.
Flowers: Large yellow flowers appearing in upper leaf axils. Flowers are bright yellow in colour, with a 4-parted style, the sepals are strongly reflexed. We measured a flower at 4.5 cm long, and 2 cm across.
Leaves: Basal rosette only in the first year. In the second year, stem leaves alternate, lower leaves have petioles, spatulate, upper leaves are sessile, lanceolate. I measured a leaf mid-stem at 8 cm long and 2 cm wide. Bottom and top of leaves pubescent.
Height: Height listed in Budd's Flora to 200 cm. We've measured plants to 41 cm tall.
Habitat: Dry soil in open areas, prairies and parklands.
Abundance: Common.
Origin: Native.
When and where photographed: The above photos were taken July 15th on sandy soil, open area among aspen groves, 20 km east of Regina, SK, and August 6th on a prairie roadside near the East Block of Grasslands National Park, about 300 km southwest of our home in Regina, SK.