Plant erect on an enormous horizontal tuber, often reaching 50 - 80 cm long, and 10 - 20 cm in diameter, part of which emerges from the ground and is indented, each zone representing growth activity for one season. LEAVES: Petioles 0.8 - 2 (-3) m high, emerging from the tuber, spiny, greyish green to pale green, or purplish mauve, mottled with very pale spots; Blade very large, divided at the apex of the petiole into 3 identical divisions, each division carrying the leaflets; those at the extreme ends, 8 - 32 x 4 - 12 cm, trapeziform, often torn into two further leaflets, which are symmetrical and equally trapeziform, at the base they are more or less decurrent on the rachis; basal leaflets 5 - 18 (-30) x 3 - 10 (-16) cm, rhomboidal to ovate, sessile and not decurrent on the rachis, the two types of leaflets are generally acuminate. INFLORESCENCE: Peduncle enveloped in a whitish violet bract, emerging also from the tuber, generally appearing after the leaf is over, green to purplish green, scattered with whitish spots, less long and spiny than the petiole; spathe 9 - 22 (-30) cm yellow, green or purple externally, often mottled with red or cream spots, generally pale green internally, slightly convolute at base, the rest boat-shaped, the apex acuminate or acute; spadix sessile, cylindric (4-) 8 - 18 (-22) x 0.6 - 1.5 cm, a lot shorter than the spathe; female flowers ca. 1/6 to 1/3 longer than the male flowers, which are cream to white; stamens prismatic, 4 sided, opening by pores; female flowers orangish, green with cream markings, or purple with pink or white markings; ovary conical surmounted or not by a style short or long, generally curved towards the base of the spadix; stigma reniform; 1-locular, ovule 1, anatropous. INFRUCTESCENCE: Berries ovoid, 18 - 10 mm, becoming green then yellow, eventually violet with purple spots or brown at the apex, or white with violet or purple apices. Apex of peduncle curving towards the sun.