Family: Onagraceae, Evening-primrose view all from this family
Description A tall, erect, usually unbranched stem with large yellow flowers in a raceme.
Flowers: 2-3" (5-7.5 cm) wide; sepals 4, reddish; petals 4, broad; becoming rather orange as they age the following day; stamens 8.
Leaves: 6-12" (15-30 cm) long, lanceolate, numerous, progressively smaller from base to top of stem.
Fruit: slender, rigid pod 1-2" (2.5-5 cm) long.
Height: 2-3' (60-90 cm).
Flower June-September.
Habitat Open slopes, road banks, and grassy areas from the plains well into the mountains.
Range Eastern Washington to Baja California; east to western Texas and southern Colorado.
Discussion Common Evening-primrose (O. biennis), found throughout most of the United States, has similar erect stems, but its petals are less than 1" (2.5 cm) long. Both are closely related to the Garden Evening-primrose (O. erythrosepala), scattered in the wild from western Washington to California, which is a taller plant, with redder sepals, paler petals about 1 1/2" (3.8 cm) long, and crinkled leaves.
