Evergreen herb with a rhizome up to 1 cm thick, which is slenderer in submerged specimens with longer internodes. Runners are 10–20 cm long and slender, occasionally featuring small "bulbil-like runners" in submerged specimens. Leaves have petioles reaching up to 25 cm in length; the blade ranges from smooth to somewhat bullate, elliptic to ovate or narrowly ovate, and measures 1–6 (8) x 3–15 (20) cm. The upper leaf surface is green to brownish or reddish and submarbled, while the lower surface is paler, typically with prominent reddish veins; the apex is acute to acuminate, the base is obtuse to cordate, and the margin is entire. The spathe is 4–10 (15) cm long and brownish on the outside. The spathe kettle is 0.6–1.2 cm long, with alveoli covering smaller or larger areas of the interior. The spathe tube is 1.5–10 cm long and usually features a dark purple-brown "collar" zone at the top. The spathe limb is 1.2–4 cm long, more or less obliquely twisted (often into a long tail), and ranges from smooth to somewhat rough; its color is greenish, yellowish, or brownish, with a dark purple-brown collar. The spadix is 1.0–1.5 cm long, bearing 4–7 pistils with rounded to ovate stigmas and 20–40 male flowers.