Schoenoplectus pungens is a species of flowering plant in the sedge family known as common threesquare, common three-square bulrush and sharp club-rush. It is a herbaceous emergent plant that is widespread across much of North and South America as well as Europe, New Zealand and Australia.

Habitat

Threesquare is found in open, sun-lit marshes and along the shores of lakes and ponds, in water up to 1 m deep. It is resistant to fire.

Description

Schoenoplectus pungens is a long-lived perennial herb up to 1.5 m tall. The foliage is dark green, rough and dense. The small flowers are grouped in dense spikelets, with of 1–7 spikelets on each stem. The seeds are brown. It is closely related to S. americanus, and many S. pungens specimens have long been misidentified as S. americanus.