Salt marsh Pink

Sabatia stellaris is an annual plant growing to 20 cm tall in the northern part of its range, and up to 50 cm tall in the south of the range.

The leaves are arranged in opposite pairs, narrow to broad elliptic in shape, with narrow leaves in Florida, and broad leaves in New England; the change in leaf shape is clinal, and cannot be separated into discrete subspecies or varieties.

The flowers are pink or white, with five or six corolla lobes ('petals'). The fruit is a dry capsule containing up to 600 seeds. — Wikipedia