Evening campion
Silene pratensis

This dioecious plant is an annual, biennial, or short-lived perennial about 2' tall, branching occasionally and more or less erect. The light green stems are terete (round in cross-section) and covered with fine hairs. The opposite leaves are up to 4" long and 2¼" across. They are light green to medium green, ovate-lanceolate, more or less sessile, smooth along the margins, and finely pubescent.