Tubers ovate-elongate, 1–3 cm long. Leaves mostly submerged, sometimes floating. Submerged leaves: petiole to 23 (–50) cm long; blade linear to elliptic or ovate, to 23 (–35) cm long, (0.5) 1.4–2.5 (–6) cm wide; base narrowly to broadly cuneate, obtuse or attenuate; margins flat or slightly undulate; apex obtuse, broadly obtuse, blunt-cuneate to acute-cuneate, truncate, or rarely retuse; veins (3–) 7–9 (–11); lacunae in 1–5 rows either side of midvein. Floating leaves: petiole to 64 cm long; blade ovate to elliptic, to 11 cm long; base cuneate, obtuse or attenuate; margins flat; apex obtuse; veins 5–9. Peduncle to 29 (–107) cm long, broadening at inflorescence base. Spathe to 1.5 cm long, caducous. Inflorescence emergent or floating, single (rarely branched), to c. 17 cm long, yellow. Flowers tightly to widely spaced, turned in all directions, bisexual. Perianth segments 2, spathulate, c. 1.5 mm long, yellow, 1-veined. Stamens 6. Carpels (2 or) 3. Fruiting carpels 4–6 mm long, 3.3–4 mm wide; beak lateral, reflexed or straight, to 1 mm long. Seeds (1–) 2–5 per fruit, cylindric to almost ovoid, 3.5–4.5 mm long, (1.1–) 1.5–2 mm wide; outer testa thick, easily removed, a second, if present, tightly adhering and difficult to remove.
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