Onagraceae : Oenothera caespitosa

Oenothera caespitosa is a perennial, acaulescent, mound forming herb from a branching caudex. Mature plants are typically 15-25 cm high and up to ~60 cm wide, with lateral roots giving rise to new plants. The leaf blades are oblanceolate to nearly linear, 3-21 cm long, 1-5 cm wide, with a winged petiole that is often as long as the blade. The margins vary greatly from almost entire to pinnately lobed to having irregular teeth that are rounded to sharp. The leaf blades, veins and margins can be variously covered with hairs or with hairs lacking. The flowers are solitary in the leaf axils, open near sunset and have a sweet scent. The floral tube is 3-8 cm long, slender and flared toward the end, often reddish in color. The sepals are 2.5-3.5 cm long lanceolate with pointed tips. The white petals are heart-shaped, 2.5-5 cm long, changing to pink after pollination. The 8 stamens are unequal in length and about 2/3 the length of the petals. The style is about as long as the petals and has a 4-lobed stigma. The fruit is a hard, lumpy, elongated capsule, 2-5 cm long with a constricted end. Gumbo lily blooms from May into August on dry, rocky prairies, hillsides and open woodlands in western and central South Dakota.