Yellow Sundrops Calylophus

Oenothera serrulata Yellow Sundrops, Yellow Evening Primrose, Plains Evening Primrose Calylophus serrulatus is a native plant found in dry prairies and mesas in western North America, particularly in the Great Plains from Canada to Texas. It is a low, shrubby, woody-based perennial, typically growing from 6 to 18 inches tall. It features narrow, lance-shaped, sessile leaves up to 2 inches long. The plant produces four-petaled, stalkless, yellow sundrops and flowers around 1 inch wide and blooming from mid-spring to mid-summer. The flowers give way to 1-inch-long seed capsules.   This plant is also known by other common names, including serrate-leaved evening primrose (due to its toothed leaves), shrubby evening primrose (because of its woody-based, shrubby habit), plains yellow primrose (indicating its natural habitat), and half-leaf sundrops (referring to its leaf length and sundrops-type flower). Similar to other sundrops, the flowers of this species do not just open in the evening b