Robust, perennial, erect, fleshy, rooted, freshwater aquatic herbs with irritant sap, forming large colonies; true stem an underground rhizome. Leaves several, forming rosulate crown at apex of massive banana-like pseudostem formed by imbricate leaf-sheaths; petiole massive, succose; sheath very broad, extending almost to non-pulvinate apex; blade sagittate; main side veins evanescent before reaching margins, finer venation striate, parallel to primary lateral veins. Inflorescences erect, appearing with leaves, much shorter than leaves, pendent in fruit. Spathe constricted centrally, basal part convolute, forming persistent fleshy tube, apical part expanded, erect, acuminate, eventually deciduous. Spadix differentiated into 4 zones: basal pistillate part with cuneiform staminodes scattered between pistils; lower sterile part with compressed prismatic sterile flowers (synandrodia); central part fertile, staminate; terminal sterile appendix bearing free to irregularly connate sterile flowers. Flowers unisexual, lacking perigon, densely congested. Staminate flower a fleshy, prismatic, truncate synandrium of 4–8 connate stamens; anthers lateral, dehiscing by oblique apical slits. Pistil shortly ovoid; ovary unilocular, with 1–2 orthotropous basal ovules; stigma subsessile, 3–6-lobed. Berries 1–2-seeded, borne in large subellipsoid infructescence surrounded by persistent spathe-tube. Seeds large, globose, lacking endosperm.
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