Schoenoplectus pungens is a species of flowering plant in the sedge family known as common threesquare,[2] common three-square bulrush[3] and sharp club-rush.

[4] It is a herbaceous emergent plant that is widespread across much of North and South America as well as Europe, New Zealand and Australia.

[1][5][6][7][8][9][10][11] Threesquare is found in open, sun-lit marshes and along the shores of lakes and ponds, in water up to 1 m (3 ft 3 in) deep.

[12][13][14][15] Schoenoplectus pungens is a long-lived perennial herb up to 1.5 m (4 ft 11 in) tall.

[13] It is closely related to S. americanus, and many S. pungens specimens have long been misidentified as S.