Aquatic; caudex 1-3 m high, to 4.5 cm thick near base, mostly 1.5-2 cm thick above, all but occasionally upper internodes armed with short prickles. Petioles 20-45 cm long; sheaths extending to ca middle or beyond, the remainder of the petiole convex below, triangulate above; blades very deeply sagittate, 15-40 cm long or more, often cuspidate at apex, the basal lobes usually acuminate, spreading, often as long as or longer than upper lobe; primary lateral veins in 3 or 4 pairs above sinus, a single basal vein directed into each basal lobe and submarginal at apex of narrow sinus. Peduncles ca one-third as long as spathe or less; spathe +/- oblong, 10-18 cm long, convolute basally even at anthesis, opening in upper half with a distinct constriction above spadix, the apex cuspidate (often twisted forward before anthesis), the tube green at base, the blade white (at least within) at anthesis, the entire spathe ultimately deciduous; spadix mostly 2-4 cm shorter than spathe; staminate part more than 1.5 cm wide, deciduous with spathe, the flowers with 3-6 stamens; lower pistillate part slender, to 4 cm long, usually ca 1 cm wide or less; pistils 1-celled; ovules 1 or 2; stigma sessile, orbicular. Fruit clusters usually broadly oblong, to 11 cm long and 8 cm wide; berries green except for roughened stigmatic area, irregularly developed (some aborted), subglobose and 2.5-3 cm wide when mature, irregularly dehiscent; seeds broad at apex, narrowed below, to 2.5 cm long. Croat 4961. Restricted on BCI to shallow water at the edge of the lake, commonly in somewhat protected areas. Flowers and fruits throughout most of the year.