About Pontederia sagittata C.Presl
This species is a perennial plant with erect, tough rhizomatous stems. Its basal leaves emerge during growth; the emergent pods measure 10–27 cm long and have an emarginate apex. Petioles can reach up to 1 m in length, are not inflated, and sometimes take on a reddish color. Leaf blades measure 8–32 cm long by 5–19 cm wide, are lanceolate in shape, with a cordate base and an acute apex. The inflorescence holds more than 50 flowers total; flowers are arranged in groups of 3, 4, or more along the peduncle, and are sessile. The peduncle measures (6–)10–20(–22) cm long, is thick, and ranges from hairy to densely hairy, rarely being glabrous. The internode between the two spathes measures (3.5–)5–16(–20) cm long. The blade of the lower spathe is 8–32 cm long by 5–19 cm wide. The upper spathe measures (3–)4–7(–9) cm long, is open along its upper half, and ends in a mucronulate apex. Flowers reach 1.5 cm across. The perianth is lilac, or rarely white, and is covered with hairy glands on its outer surface; outer perianth lobes are approximately 6 mm long, and inner perianth lobes are also approximately 6 mm long. Long filaments measure 6–9 mm, and bear glandular hairs on their upper third; short filaments measure 0.7–3.5 mm, and also bear glandular hairs on their upper third. Anthers of the upper whorl are 0.75–1 mm long and yellow; anthers of the lower whorl are 0.55–0.85 mm long and also yellow. The pistil measures 3–6 mm long; the style has hairs near its apex, and the stigma is 3-lobed. Utricles are 5–6 mm long, deltiform in shape, with smooth rib edges. Seeds are 2.3–2.5 mm long, smooth, obovoid, and covered by a mucilaginous layer that has an oily appearance. Pontederia sagittata has a discontinuous native distribution, occurring from Mexico to Central America, and separately in eastern and southern Brazil. It grows on the edges of rivers, lagoons, ponds, and swamps, at altitudes up to 1,500 m (4,900 ft).
