Description: An erect hairless perennial plant with stems that are square in cross-section and with the four angles winged, reaching two feet in height and with stolons produced from the base. Flowers of the usual St. John's wort type, about 1/3 inch across; leaves about 3/4 inch long with small translucent dots.

Native; common and widespread in damp grassy and marshy places.

All names: Hypericum tetrapterum Fries; Hypericum quadrangulum L.; Hypericum acutum Moench; Hypericum quadratum Stokes

Distribution Map from NBN: Hypericum tetrapterum at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Hypericum tetrapterum at iNaturalist World Species Observations database.