Silene latifolia or Melandrium
dioicum is dioecious (male and female flowers are on separate plants). A male plant is shown in the first
photo, and a female plant is pictured in the second photo. The calyx below the flower is inflated and pubescent. White Campion is a non-native plant, growing to 3-feet tall on disturbed meadows or roadsides.
Compare to Silene antirrhina, which has smaller flowers and a non-inflated, glabrous calyx.