Pontederia sagittata is a species of aquatic plant belonging to the family Pontederiaceae.
It is a perennial plant with erect, rhizomatous tough stems. Basal leaves, emerging; pods 10âÂÂ27 cm, the apex emarginate; petioles up to 1 m, not inflated, sometimes reddish; Blades 8-32 x 5âÂÂ19 cm, lanceolate, the base cordate, the apex acute. Inflorescence with more than 50 flowers; flowers arranged in groups of 3, 4 or more along the peduncle, sessile; peduncle (6-)10-20(-22) cm, thick, hairy to hairy or rarely glabrous; internode between spathes (3.5-)5-16(-20) cm; blade of lower spathe 8-32 x 5âÂÂ19 cm; upper spathe (3-)4-7(-9) cm, open on the upper 1/2, the apex mucronulate. 1.5 cm flowers. Perianth lilac or rarely white, externally hairy-glandular; outer lobes c. 6mm; internal lobes c. 6mm Long filaments 6âÂÂ9 mm, with glandular hairs in the upper 1/3, short ones 0.7-3.5 mm, with glandular hairs in the upper 1/3; anthers of upper whorl 0.75âÂÂ1 mm, yellow; anthers of lower whorl 0.55-0.85 mm, yellow. Pistil 3âÂÂ6 mm; style hairy towards apex; stigma 3-lobed. Utricles 5âÂÂ6 mm, deltiform, with smooth rib edges; seeds 2.3-2.5 mm, smooth, obovoid, covered by a mucilaginous layer with an oily appearance.
Pontederia sagittata was first described by Carl Presl in 1827. It has sometimes been reduced to a form or variety of Pontederia cordata.
Pontederia sagittata has a discontinuous distribution, being native from Mexico to Central America and then eastern and southern Brazil. It is found on the edges of rivers, lagoons, ponds, and swamps, at altitudes of up to .