White Eveningprimrose (Oenothera speciosa)
Oenothera Speciosa Nutt.
White eveningprimrose is an erect perennial 1-2 ft tall arising from a slender rhizome. The alternate leaves are oblong-lanceolate, entire to dentate-lobed to pinnatifid, and glabrous to canescent. The flowers are sessile in the axils of the upper leaves, forming spicate clusters. The corolla is composed of 4 white, sometimes grading to pink, thin petals. The calyx forms a long tube extending to the inferior ovary (hypanthium). The stigma is large and 4-lobed. The fruit is a winged capsule 1/4-1/2 in. long. The flowers open toward evening and close during the warm part of the day. The plants are usually found in large colonies, particularly in disturbed areas such as roadside ditches.