Oenothera primiveris  Desert Evening Primrose
BIENNIAL.  First-year plants have only a rosette of leaves; plants bloom in their second year.  Leaves fuzzy, dark green, occasionally spotted with purple, variable in shape but usually elongate, with pointed tips and prominent white midveins.  Leaves on mature plants have many deep, rounded lobes.  Leaves on first-year plants simply have wavy edges.  Flowers have a distinct stalk, four heart-shaped yellow petals, and a stigma that is divided into four threadlike segments.  Flowers open at dusk and close in bright sunlight, so the best time to see them is just after sunrise.  One of the earliest spring wildflowers, blooming in March-early April.  Southern Arizona has several Oenothera species but this one is the most common.  Frequent in the Empires after wet winters, usually on bajadas and other bare, clay-rich, gravelly soil.
FAMILY:  Onagraceae (Evening Primrose Family)