Flower:

Flowers arise in dense, cylindrical spike-like racemes at the top of the plant and the tips of branching stems. Flowers are flanked by a pair of spreading, oval to egg-shaped, petal-like sepals, each up to ¼ inch (4 to 6 mm) long, about half as wide, rounded to blunt at the tip and have a conspicuous midvein. Three small petals are fused into a short column in the center, fringed with stubby yellow lobes at the tip. Color ranges from pink to purple, rarely white, though commonly fades with age. Flower clusters are about ½ to ¾ inch (to 2 cm) in diameter and elongate during the growing season, with flowers blooming at the tip and fruit forming below.

Leaves and stem:

Leaves are alternate, up to 1½ inches (1 to 4 cm) long, linear to narrowly elliptic, widest near the middle, blunt to pointed at the tip, toothless, hairless, and stalkless or nearly so. Stems are square or ribbed, hairless, usually branched in the upper plant.

Fruit:

Fruit is a small round capsule containing 2 hairy seeds. The lateral sepals become erect as the capsule develops, overlapping like fish scales and the color often fading to pale pink or greenish white. Sepals and capsules both drop off at maturity leaving a tiny floral bract on the stem.

Notes:

The flowers are vaguely similar to those of the related Cross-leaved Milkwort (Polygala cruciata), which is far less common though they may be growing side by side; it has leaves typically whorled in 4s, is shorter statured, and the sepals remain spreading like wings throughout the season.