Leaves few–many (often 3–15 per plant); petiole usually 5–20 cm. long; blades 2–8 cm. long and 3–16 mm. wide, oval to linear-oblong, with 5–7 parallel main nerves, cuneate to truncate base and blunt or subacute tip, more rarely the blades have a long attenuate base and are then not well separated from the petiole.
Flowers mauve to lilac, densely set in unbranched spikes and facing in all directions; peduncle greenish, but often white to mauve below, dull maroon to brown above, 5–30 cm. long (depending on the depth of the water) and 0.5–2.5 mm. thick; mature spathe not seen, very early caducous.
Spike 6–30 mm. long and 5–10 mm. wide, 10–30-flowered, sometimes elongating to 40 mm. long when fruiting.
Tuber oval to elongate or cylindrical, 10–25 mm. long and ±15 mm. thick, the upper part with numerous whitish roots.
Tepals 2, purple or mauve, obovate or spathulate, 2–6 mm. long and 1–1.4 mm. wide, 1-nerved, long-persistent.
Stamens 6 or 1 or lacking in apomictic specimens; filaments 1.5–3 mm. long, purple, thickened towards the base; anthers yellow to dark brown, 0.3–0.7 mm. long, the connective sometimes with a flattened conical protuberance ± 1 mm. long.
Follicles greenish, 3.5–6 mm. long and ±1.5 mm. wide including a ± 1.5 mm. long narrow beak which is often dark purple at the tip.
Ovaries 3–8, mauve, with 2–9 ovules.