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 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, but are open for the entire day. The leaves of this fascinating prairie plant align with their edges facing the intense mid-day sun as an adaptive way of minimizing water loss.