Calylophus serrulatus is native to 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 which typically grows from 6-18" tall. Features narrow, lance-shaped, sessile leaves (to 2" long). Four-petaled, stalkless, yellow sundrop flowers (to 1" wide) bloom mid-spring to mid-summer. Flowers give way to 1" long seed capsules.
Additional common names for this plant include serrate-leaved evening primrose (for toothed leaves), shrubby evening primrose (for woody-based, shrubby habit), plains yellow primrose (for where it grows) and halfleaf sundrop (for leaf length and sundrop-type flower). As with other sundrops, the flowers of this species do not just open in the evening, but are open for the entire day. Leaves of this interesting prairie plant line up with their edges facing the intense mid-day sun as an adaptive way of minimizing water loss.
