Scientific Family
Onagraceae
Synonyms
Oenothera serrulata, Calylophus australis, Meriolix serrulata, Meriolix intermedia, Meriolix oblanceolata
Other common names
yellow evening primrose
halfshrub sundrop
plains evening primrose
Plant type
Forbs and Subshrubs
Origin
Native
Lifecycle
Perennial
Height
4 to 20 inches
Riparian
No
Subshrub with many branches and an upright bushy growth pattern; grows into large clump, woody only at the base. Flowers open in the morning and close in late afternoon fading from yellow to orange or pink with age. Leaves may stay green in mild winters.
Stems typically clustered, woody below, often covered with short stiff appressed hairs; leaves numerous, narrow; floral cup funnel-form, yellow, open daytime, sessile, upper axils, stigma disc-like, often shallowly 4-lobed; stamens unequal.
Habitat
Sandy and rocky areas, dry open plains, prairies and bluffs.
Plant Community
Pinyon Juniper Woodlands
Montane Conifer Forest
Interior Chaparral
Grasslands
Low elevation
4000
High elevation
7000
Flower Characteristics
Flowers single, 1/2 to 1 inch across with 4 rounded petals that are often wrinkled like crumpled tissue paper with wavy edges and a rounded notch at the tip; flowers are stalkless but sit on top of a hairy, funnel-shaped floral tube resembling a stalk.
Flower color
Yellow, orange or pink with age
Flower shape
Regular
Tubular
Yes
First bloom month
June
Last bloom month
July
Flower clusters
None
Leaf and Stem Characteristics
Linear leaves are 3/4 to 2-1/2 inches long with short, fine, gray or white hairs(canescent);leaf margins are often sharply toothed but can be smooth; leaves can be stalkless (sessile) or have a short stalk (petiole). Green to brown stems have stiff hairs.
Leaf type
Simple
Leaf color
Grayish-green
Leaf shape
Narrow
Leaf margin
Toothed
Leaves clasp
No
Leaf hairs
Leaves & stems
Spines
No
Fruit and Seed Characteristics
Linear, cylindrical, stemless capsule is roundly 4-angled, 1/2 to 1 inch long and covered with short, fine, gray or white hairs; fruit is dry and splits open when ripe, releasing many seeds.
Fruit type
Capsule
Fruit color
Gray, white
Seeds are 1/16 inch long, dark-colored and sharply-angled.