Lythrum alatum Pursh

Species Identification and Growth Habit

Winged loosestrife (Lythrum alatum Pursh) is an upright, branching herbaceous plant that grows to about one metre tall. Its lower stems are woody, square in cross-section, and have slightly winged angles.

Leaf Characteristics

Most leaves are opposite, stalk-less, broadly oblong, taper toward the tip, and have smooth, untoothed edges. Flowers grow singly or in pairs in the axils of the much reduced upper leaves.

Calyx Structure

The calyx forms a tube about 0.6 millimetres long, with six pointed teeth. The six rose-pink petals, each marked with a magenta central vein, measure about 5 millimetres long and 2 millimetres wide.

Reproductive Organ Morphology

This species has six stamens with pink filaments and purple anthers; its stigma is white, its style is green, and it has a superior ovary. The fruit is an elongated capsule holding numerous tiny seeds.

Habitat and Distribution

Winged loosestrife grows in wet meadows, fens, pond and lake margins, alongside streams, and near railroads.