Amorphophallus impressus Ittenb.

Tuber unknown. Leaf solitary, c. 120 cm long; petiole c. 100 cm long, c. 2.5 cm in diameter at the base, green with purple spots; lamina green, c. 100 cm in diameter, rhachises with broad-triangular to oval wings, terminal leaflets elongate-oval, 4−10 7 1−3 cm, acuminate, margin slightly undulate or dentate. Cataphylls 2(−4), the outer one 10−14 cm long, the innermost 25−30 cm long, longer than spathe and peduncle together, whitish to pink and with greenish to brownish oval to roundish spots. Inflorescence sessile, appearing before the leaf, short-peduncled, c. 50−70 cm long; peduncle 5−10 cm long, 1−1.5 cm in diameter, smooth, brown-green with or without green or olive spots, to the spathe grading into purple. Spathe 12−25 cm long, separated by a strong constriction in a depressed, urceolate tube and a rimshaped to elongate-triangular limb; tube 3.5−10 x 4−9 cm, outside creamy to flesh-coloured, the lower part greyish brownish to green, with dark green veins and small green to brown spots; inside pinkish, purple to reddish brown, lower part with small, tongue-shaped colourless or purple or reddish brown emergences of 0.3−1 x 0.5 mm higher up reduced in size and causing the inside surface to be rough; limb strongly undulate, on the side of the longest cataphyll 4−6 cm long, on the other side elongate-triangular and 6−15 cm long, outside dark green to brownish purple, with thick purple veins, inside pink to purple, margin maroon. Spadix sessile or stipitate for 1−6 mm, 18−40 cm long, longer than spathe; pistillate zone cylindrical, 1−3 x 0.8−1.2 cm, flowers congested or somewhat distant; staminate zone obconical to ovoid, narrowed at base, 1.5−4 x 1−3 cm, flowers congested; sterile zone between pistillate and staminate zone 1−10 mm long; appendix 20−35 cm long, thick-conical to slightly clavate, above the staminate zone slightly constricted, 2−4 cm in diameter at the base, dark purple, verruculose; staminodes absent; ratio of pistillate to staminate zone length 0.4−0.6 : 1. Pistillate flowers 2−4 mm long; ovaries globose-ovoid, 1.5−2 x 1.5−2 mm, yellowish green or bright green, (1−)2(−3)-locular, stigma sessile, 1−2 x 1−2 mm, dark yellow, papillose, with 2(−3) small roundish humps or rarely roundish and smooth. Staminate flowers 0.9−1.6 7 1−1.9 mm, with 2−5 stamens; filaments absent or only 0.1−0.2 mm long; anthers free, elongate-ovoid to cubic, creamy to yellowish orange; connective with two small grooves, brown; pores elongate-oval, one apical to subapical pore per theca (rarely two pores per theca). Infructescence unknown. Pollen inaperturate, exine smooth (psilate).