Alismataceae : Sagittaria cuneata
Arrowhead, Duck potato
Sagittaria cuneata is a perennial aquatic herb growing from a white corm. The leaves are variable in shape and can be submerged, floating or emersed from the water, with many of them being arrow shaped. The submerged parts of the plant look different from those growing above the surface or on land. Petioles of emersed leaves are 3-50 cm long while those of floating leaves may reach 100 cm. The blades of the leaves are 5-20 cm long with two smaller, pointed lobes opposite the larger tip that makes up half or more of the leaf length. The plant is monoecious, bearing both male and female flowers. The inflorescence rises above the surface of the water on a triangular peduncle 10–50 cm long; a raceme made up of 2–10 whorls of flowers, the lowest node bearing female flowers and upper ones bearing male flowers. Each flower is up to 2.5 mm in diameter with 3 recurved sepal 4-9 mm long and white petals that are about twice the length of the sepals. The fruit are achenes attached to fruiting heads that are 0.8 to 1.5 cm wide. Arrowhead blooms from June through September in ponds, lake shores and streamside throughout South Dakota.