We have a dozen different kinds of Rosegentians (Sabatias) or Marsh pinks that grow here in north Florida; nine of these have pink petals and four have white petals.
Of the four species with five pink petals, this one (Sabatia grandiflora) has the largest flower (larger than a quarter coin). It grows almost totally in Florida. It has a yellow center in the blossom, and a long twisted pistil that is distinctive. It can reach up to two feet in height and often grows in groups in sunny damp areas. It is an annual, and blooms in the summer.