Flora of New Zealand Series

Three-square

Rhizomatous. Stems 3-angled, soft, sea-green, usually to 60 cm but occasionally to > 1 m high. Leaves 1-4, becoming 3-angled like stems. Inflorescence a compact head of 1-4 sessile, dark brown spikelets with a trigonous bract.

N. Southwards from Coromandel and lower Waikato River, scattered; not known from Taranaki. S. Scattered; rare in Westland and Fiordland. Ch. Salt marshes and brackish swamps, usually coastal but inland on Waikato River, Canterbury at Pareora Gorge and in Central Otago. (W. Europe, America, Australia)

Formerly treated in N.Z. as S. americanus Pers. Schuyler (Rhodora 76, 1974, 51-52) examined the type specimens of S. americanus Pers. and S. pungens Vahl and found that the names had been wrongly applied in America.

S. americanus with strongly-winged stems is confined to N. and S. America, whereas the name S. pungens should be applied to the triangular-stemmed sp., which is more widespread.

Troublesome weed in reclaimed coastal areas; breaks up footpaths and gutter channels in built-up coastal areas.

B. Slender rhizome or creeping stems.