Protologue: Rumphia 1 (1837): 143
Amorphophallus blumei (Schott) Engl. [illegitimate]; Amorphophallus burmanicus Hook. f.; Amorphophallus carnosus Engl.; Amorphophallus erubescens Hett.; Amorphophallus oncophyllus Prain ex Hook. f.; Amorphophallus planus Teijsm. & Binn.; Amorphophallus timorensis Alderw.; Amorphophallus muelleri (Blume) Schott; Conophallus blumei Schott [illegitimate]; Conophallus muelleri (Blume) Miq.; Conophallus planus (Teijsm. & Binn.) Miq.
Tuber globose or depressed-globose, dark brown, yellow or orange inside, to 28 cm in diam., weighing to c. 3 kg., developing no annual offsets, root scars annuliform, swollen. Leaf solitary, occasionally two on one tuber. Petiole smooth, 40-180 cm long, 1-8 cm in diam. (base), green, olive green, brownish-green or almost black, with numerous large elongate elliptic, diamond shaped or stripe-like, pale green spots, and sometimes with an additional high number of small, pale green, rounded dots. Lamina highly dissected, 75-200 cm in diam., in the centre, carrying epiphyllar bulbils on the major branchings and on the most distal branches. Leaflets elongate elliptic or narrowly elongate-elliptic, acuminate, base strongly and broadly decurrent, 10-40 cm long, 4-15 cm in diam., upper side green or dark green with a narrow, whitish or pinkish-red margin, especially when young, leaflets of seedlings dark emerald green with a reddish flush and strong red margins. Bulbils depressed, rounded or elongate, greyish-brown, 0.5-6 cm in diam., 1-40 per leaf. Inflorescence solitary, long-peduncled. Peduncle as petiole, 30-60 cm long, 0.5-3 cm in diam. (base). Spathe broader than long, rarely slightly the reverse, very broadly triangular or transversely elliptic, coriaceous, marcescent, 7.5-32 cm long, 6-36 cm in diam., base strongly convolute and slightly or clearly constricted at the top, limb semi erect or spreading, often partly horizontal, margin reflexed, ± suddenly narrowed to the top, the latter very obtuse, base within nearly smooth or with numerous small, elongate warts, these often confluent, outside base pale green or pale dirty pinkish with, usually transversely elongate, whitish spots and few small, blackish-green dots, upwards grading to brownish-purple, pink or dark greyish-green, with large, ± iso-diametrical white spots, inside base dark pink, bright pale pink or pale yellowish pink, upwards grading to purplish, pink, dark pink, dark brownish pink or brownish with dirty pale greenish and dirty pale brown, transversely oval spots, or the latter white. Spadix sessile or stipitate or intermediate, longer than spathe, 8-40 cm long, drying in fruit and remaining, stipe 0.1-1.5 cm long. Female zone cylindric or slightly fusiform, 1.5-10 cm long, 1-5 cm in diam.; flowers congested, lax or intermediate, the lowermost flowers more loosely arranged than the upper ones. Male zone cylindric, obconic or fusiform, 2-9 cm long, 0.9-6 cm in diam., in large specimens usually laterally compressed; flowers congested. Appendix thick-walled, fusiform-conic, top subacute or acute, laterally compressed to various degrees, surface with numerous small, punctiform depressions and with or without some irregular, larger shallow depressions, base with staminodes intermediate between stamens and the appendix wall, 3-22 cm long, 1.5-9 cm in diam., pale pinkish, yellowish or pale brownish, developing an offensive stench of “Durian or old cabbage”. Flowers unisexual, occasionally intermediately bisexual with reduced pistil surrounded by few stamens. Ovaries shortly stipitate, depressed, 3-3.5 mm in diam., 1-1.5 mm high, lower half reddish-purple, upper half pale pink, 2-3-locular, one basal ovule per locule, stipe c. 0.5 mm long. Style short and thick, largely pale pink but uppermost zone reddish-purple, 0.3-1 mm long, 0.8-1 mm in diam. Stigma large but diameter always slightly smaller than ovary, circular, quadrangular or slightly oval in cross-section, flattened, subhemispheric or hemispheric, with a shallow, elongate or three-rayed central depression or shallowly 3-4-lobate, margins reflexed, occasionally with two or three equidistant, small notches, dirty pale yellow, 1-2 mm in diam., 0.8-1.5 mm high, surface micro-rugose or micro-scabrate/echinate, copiously covered with a very sticky, viscous fluid. Male flowers consisting of 3-5 stamens. Anthers sessile, elongate, irregularly prismatic or rectangular in cross-section, truncate, dirty pale yellow, 1-2 mm long, 0.8-2 mm in diam., pores apical, small, elongate, oval at anthesis, most thecae containing an amorphous mass at anthesis, only a few ones extruding very little, whitish “pollen”. Infructescence cylindric, consisting of to 1000 berries. Berries elongate or elongate-ovate, apex slightly depressed, 1.2-1.8 cm long, green ripening bright red, 2- or 3-seeded.
Sumatera, Java, South Kalimantan, Flores and Timor Timur (Indonesia), Andaman Islands through Myanmar, northern Thailand (Hetterscheid & Ittenbach 1996).
Habitat: Thickets, disturbed areas, forest edges and village groves, at c. 900 m altitude.
Amorphophallus muelleri is easily recognised in flower by the constricted spathe, the pink inner side of the lower part of the spathe and the huge, 3-4 lobed stigmas. In leaf, the epiphyllar bulbils differentiate it from all other Indonesian species. It is known to be a triploid (3n = 39) and sets (pseudo) seeds easily without pollination.
Amorphophallus muelleri has been intensively cultivated in Java, notably East Java for the glucomannan in its tubers.
To date, many Indonesian people still use the name of Amorphophallus oncophyllus (synonym) instead of Amorphophallus muelleri.