Whitest evening-primrose

Description:

from Native Plant Database, Lady Bird Johnson Wildflower Center: "This is a winter annual with stems up to 20 in long spreading horizontally in a circle from the root. Basal leaves are spatula-shaped; the upper leaves are pinnately cleft into wavy-margined, narrow lobes. Showy flowers are made up of four, white, heart-shaped petals. Flowers open near sunset but remain open for several days."

Habitat:

from Native Plant Database, Lady Bird Johnson Wildflower Center: "MT to AZ, e. to w. ND, w. KS, TX & n. Mex. Sandy roadsides and fields."

Notes:

This plant was growing in my yard in Estes Park. The soil is sandy/gravelly and the turf is native shortgrass prairie.