Lythrum hyssopifolia is an annual herb 10-60 cm tall, pale green, stem 4-angled.
Leaves mostly alternate, stalkless, blade 1-3 cm long, 0.1-0.7 cm wide, linear to elliptic.
Flowers pale purple, radially symmetrical, petals 4-6, 0.2-0.3 cm long, wedge-shaped (cuneate); calyx tubular, lobes 4-6, short; appendages between calyx lobes longer than lobes; stamens 4-6, shorter than calyx tube; flowers 1-2 in leaf axils; blooms and fruits June-Sept.
Fruit a dry capsule.
Wetland status: OBL.
Frequency in NYC: Very infrequent..
Habitat: Brackish marshes.