The species is a weedy annual. The leaves are opposite and entire. They are linear to oblong and can be up to 3 cm long. They have fine hairs and smaller leaves develop in axils of the stems of larger leaves. The flowers develop in a flat top cluster from a stem that can grow up to 50 cm tall. The flowers have five sepals, five petals that are white, and bloom from early spring to late summer, depending on elevation. Fruits are round capsules that open at the tip with teeth and contain many brown colored seeds.
Get close to see the ornate, deeply notched petals on these tiny blooms. This perennial is an important nectar plant for butterflies.