Angiosperms: Dicotyledons

Onagraceae
Evening Primrose Family

• Stem: perennial; 1’ to 1 1/2’ tall; usually unbranched; often several stems from the same root crown; hairy.
• Leaves: alternate; oval, wider above the middle; 1 1/2” by 3/16” and smaller (especially in western Iowa); sessile; toothed margins (six to eight teeth per inch); hairy below, smooth above.
• Inflorescence: spikes on leafy flower stalks from the stem tip and upper leaf axils.
• Flowers: petals yellow, irregularly lobed, 1/4” long on 1/4” floral tube atop hairy ovary (inferior ovary), 3/8” long; sepals 3/16” long, not reflexed; flowering from mid-June to mid-July.
• Fruits: squarish capsule, 3/4” long by 3/32” in diameter, hairy; fruiting begins in late June.
• Habitat: frequent in western Iowa to very uncommon in eastern Iowa; on dry and rocky prairies to Loess Hills prairies.
• Bibliography from Biodiversity Heritage Library
• Vascular Plants of Iowa