STEM: erect or hanging, sometimes tortuose, up to 8 m long, 2 5-7 cm diam., woody-fibrous, cut stem and roots exuding viscous resin which turns yellow-orange; adventitious roots very long in epiphytic plants, hanging down to ground, up to 1 cm diam., sparingly branched; internodes 0.1-8 cm long, dark green, smooth; prophyll scars 0.1-1 cm long, paler and usually much shorter than internodes; intravaginal squamules usually lacking, few when present, c. 4 mm long, 3 mm wide at base, flattened-triangular, acuminate, not persisting; foliage leaf scars transverse-elliptic, or suborbicular to elliptic, situated at apical end of internode, 2.5-3.2 cm long, 2-4 cm wide, pale grey to whitish. LEAF: prophyll 20-40 cm long, yellow-green; petiole 36-140 cm long, apex densely and minutely rugulose-verruculose, 0.5-1.1 cm diam., basally transverse-elliptic to terete in cross-section, with broadly triangular adaxial ridge, dull green, sheath 4.5-20 cm long; leaf blade pedately compound, transverse-elliptic to reniform in outline, overall length up to 62 cm, overall width to 80 cm; leaflets 10-20, pendent, sessile or rarely shortly petiolulate, borne on a pair of retrorse rachises, widely separated centrally, becoming progressively more crowded laterally, upper surface dark glossy green, lower surface paler and dull, venation concolorous with blade, leaflet midrib excurrent into an apiculum only in central leaflet, no primary lateral veins present, cross veinlets of finest parallel veins sometimes distinct in dried material, central leaflet as long as or shorter than adjacent lateral leaflets, 18-50 cm long, 5-10 cm wide, oblong-elliptic, acuminate, base acute to rounded, first lateral leaflets inserted 3.5-6.5 cm from central leaflet, up to 50 cm long, 11 cm wide, acuminate to acute, otherwise as central leaflet, outermost lateral leaflets progressively smaller. INFLORESCENCE: 1 per leaf axil, rarely 2 and then the second inflorescence subtended by a 2-keeled prophyll; peduncle shorter than spathe, (2.5- )3.5 - 7(-10) cm long, 1-2.5 cm diam. at apex; spathe 11,5-24(-30) cm long, (2-)3-5(-6) cm diam. at middle, ± cylindric, decurrent for 2-6 cm, outer surface glossy green with scattered, frequent to numerous, paler punctate extrafloral nectaries, inner surface glossy cream, resin secretion more abundant in lower half; spadix 11.5-20 cm long, fertile male zone 2-4(-5) cm long, 1.2-1.9 cm diam., thickest at base, conic, acute-acuminate at apex, sterile male zone 4.5-10 cm long, 1.4-2.8 cm diam., subcylindric, slightly thicker towards base, female zone 2.5-6.5 cm long, (1.3-)2 -2.5 cm diam., apical portion cylindric or tapering to apex. FLOWERS: stamens 3-4 per flower, (2-)3.5.5 mm long, 0.5-1 mm wide at apex, tapering to base; staminodes 3-5.5 mm long, lowermost longer and distinctly stipitate, (0.5 -)0.8- 1.3 mm wide and truncate at apex, cylindric-prismatic; gynoecium 5-6 mm long, ovary subcylindric, 3.5-4 mm diam., tapering to base, septa with scattered raphide cells, locules 10-26, ovules 4- 13 per locule, with abundant raphide cells at micropylar end, inserted on axile placenta extending to apex or apical third of locule, style body lacking raphide cell concentration around stylar canals, compitum a ± shallow, circular channel not penetrating far into style body, shallowly ridged on outer face, style crown weakly lobed, style lobes short, spreading widely, central dome overtopping style crown, with irregularly lobed raised margin, often with shallow central pit, stylar canals long, entering locules subapically or in upper third, stigma 3-4.5 mm wide, stigma hairs covering inner face of compitum and margins but not centre of central dome, tannin hairs numerous. INFRUCTESCENCE: berry 1.5-2 cm long, 1-1.3 cm diam., ± cylindric, rounded at apex, greenish-white when ripe; seed 3.5-4.5 mm long, 1.2-2.5 mm diam., subcylindric, often tapering slightly at one end, raphe forming prominent, fleshy aril along one side of seed, filled with oily droplets, testa with numerous raphide cells at micropylar end, micropyle umbonulate.
Terrestrial with very abbreviated internodes or climbing and hemi-epiphytic with longer internodes; in permanently flooded (igapó) forest, seasonally flooded (várzea) forest, terra firme forest, Amazonian 'caatinga' (somewhat stunted, xeromorphic forests on nutrient-poor soils, especially white sand), or closed secondary forest by roadsides, common on river margins both as terrestrial and epiphytic plants.