Sagittaria teres

Sagittaria teres is an arrowhead species that in the USA is distributed mainly on the Atlantic coastal plain. There it occurs on sandy pond margins and in swamps with acidic water.¹ The species name S. teres is generally known in the aquarium hobby, but is used erroneously. The plant available in the trade under this name (often with the incorrect spelling “Sagittaria terres”) is not S. teres, but Sagittaria subulata.²

The true Sagittaria teres is an unusual species that differs greatly from S. subulata. It is characterised above all by its subulate, rush-like leaves, i.e. the leaves have an almost circular cross-section and taper to a point, similar to the leaves of shoreweed (Littorella uniflora). The species name refers to this leaf shape (teres = “terete, cylindrical”). The emersed leaves of S. teres grow up to 60 cm long and 1.5 to 7 mm wide, while the submersed leaves reach 3.5 to 18.5 cm in length and 1.5 to 4 mm in width. The plant forms runners and underground tubers. At its natural sites this arrowhead flowers in summer (July-September). The inflorescences are erect, up to 80 cm tall, unbranched and bear 1 to 4 whorls of flowers approx. 1.5 cm across.¹

Sagittaria teres is described in aquarium literature, but, at least at present, is certainly not in cultivation as an aquarium plant. The true Sagittaria teres is not available in the trade.