Amorphophallus paeoniifolius (Dennst.) Nicolson

CATE Araceae, 17 Dec 2011. araceae.e-monocot.org

Phenology

Fl. Apr–May, fr. Oct–Nov. The leaf is present from September to April.

General Description

Tuber dark brown, depressed globose, ca. 20cm high, to ca. 30cm in diam., weighing up to ca. 15kg; root scars prominent, annulate; offsets produced every season, thick and rhizomatous, to ca. 10 × 4cm. Leaves 1 or 2; petiole background pale to dark green or blackish green, usually with large and small pale blotches and numerous tiny dark dots, large blotches often confluent, especially near base, petiole to ca. 2 m × 20cm, shallowly corrugate to strongly echinate-verrucate; leaf blade highly dissected, to ca. 3m in diam.; rachises narrowly or broadly winged almost to base; leaflets abaxially mid-green or pale green, adaxially mid-green, orbicular, oval, ovate, obovate, elliptic, elliptic-oblong, elliptic-lanceolate, or lanceolate, 3–35 × 2–12cm, apex acuminate. Inflorescence shortly pedunculate; peduncle 3–20 × 1–8cm, usually paler and more glabrous than petioles. Spathe campanulate, broader than long, 10–45 × 15–60cm, base and limb often separated by a shallow constriction; limb spreading, background ranging from pale green to dark brown, usually with both large and small, orbicular paler spots, base inside proximal part deep maroon, distal part dirty whitish or very pale pinkish, limb outside as base but with more prominent maroon flushes, especially near margin, limb inside usually glossy dark maroon, strongly undulate, base outside very variable, base within densely verrucate, verrucae variable, mostly conic, fleshy. Spadix giving off a stench of rotting meat, sessile, shorter or longer than spathe, 7–70cm; female zone cylindric, 3–25 × 1–12cm, flowers congested or slightly distant; ovary entirely pale green or largely maroon with a whitish base, depressed, orbicular in cross section, 1.5–2.5mm high, 3–5mm in diam., 2- or 3-loculed; style maroon, 3–15mm, slender, 1–1.5mm in diam.; stigma pale or deep yellow, oval or triangular in cross section, large, 3–5mm high, 4–7mm in diam., often strongly laterally compressed, then cordate in longitudinal section, verruculose, shallowly or deeply 2- or 3-lobed, lobes rounded or conic, sometimes with a strong groove on outward side; male zone cylindric or strongly obconic, 2.5–15cm, 1–10cm in diam. at base, 1–20cm in diam. at apex, flowers congested; male flowers consisting of 4–6 stamens; stamens 4–6mm; filaments ca. 0.5 mm, connate; anthers off-white, cylindric, 3.5–5.5 × ca. 1.5mm, subtruncate; pollen psilate; appendix very variable, glossy dark maroon, rarely pinkish or yellow, inflated, globose, depressed globose, ovoid, or triangular-conic (pyramidal), 1.5–30cm, 1.2–30cm in diam. (slightly above base), minutely granulate, glabrous or with various folds and/or irregular shallow depressions, base often with flattened, staminodal structures, apex obtuse or ± acute. Infructescence long pedunculate; peduncle stretching strongly after fertilization, 20–100cm, becoming uniformly tan, with very numerous narrow, transverse cracks; fruiting zone cylindric, 10–50 × 3–8cm. Berries closely set or slightly distant, ripening from green through yellow to bright red, elongate, 1.5–2 cm × 8–10mm. Tuber flattened globose, 10-40 cm in diameter, brown. LEAF solitary, more rarely 2; 2-3 membranous cataphylls, of different lengths, accompanying the leafs or the inflorescence; petiole 50-150 x 2-4 cm in diameter, scabrid to slightly verruculose, pale green to greenish, with paler mottlings. Leaf blade 50-150 cm diameter, pale green, divided into three main parts, the segments divided, bifurcate and pinnatisect, incisions up to the primary vein; lobes oblong elliptic, cuspidate to acuminate, 5-15 cm long, oblique and decurrent on one side. INFLORESCENCE: Peduncle short, 5-20 cm long, ca. 3 cm wide, mottled reaching 120 cm in fruit. Spathe campanulate to subcampanulate, coriaceous to fleshy, 20-30 x 25-35 cm, margin ± curved and pleated, the external surface greenish to reddish and mottled whitish, the internal surface purple and verruculose at the base, yellow in the central zone, the edges purple on the upper part. Spadix 25-30 cm long; female zone cylindric, 5-12 cm; male zone obconic, 4-6 x 2-4 (at the base), 4-6 (towards the top) cm; Appendix globose to subglobose, or globose-conoid 7-15 x 10-15 cm (at the base), purple, ± reddish. Male flowers 4-5 mm tall; anthers subsessile, oblong. Female flowers 10-17 mm long; ovary 2-3 mm tall, purple, usually 2-locular (rarely 3); Style purple, 8-14 mm long, cylindric; stigma yellowish with 2-3 lobes ca. 1.5 mm diameter. INFRUCTESCENCE: Berries ovoid to oblong, red, 10-13mm long; 2 seeds (rarely 3). Chromosome number 2n=28.

Habitat

Secondary conditions, secondary forests or highly disturbed areas, in dappled shade or fully exposed. Terrestrial or on humus accumulated on rocks; shady places.

Vernacular

you bing mo yu

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

Araceae, S.J. Mayo. Flora of Tropical East Africa. 1985

Diagnostic

It is quite distinct from the native East African species in the subglobose to broadly conic, coarsely furrowed and crumpled spadix appendix, surrounded by a campaniform purple spathe.

Kew Species Profiles

General Description

Elephant yam is a striking aroid with a flower spike crowned with a bulbous maroon knob and encircled by a fleshy maroon and green-blotched bract. The solitary leaf, which emerges after the flowering parts, resembles a small tree.

Amorphophallus paeoniifolius has been in cultivation throughout tropical Asia for centuries. The tubers are the third most important carbohydrate source after rice and maize in Indonesia. They are also consumed widely in India and Sri Lanka, although elsewhere they are seen as a famine crop, to be used when more popular staples, such as rice, are in short supply.

Elephant yam belongs to the same genus as the crowd-pulling titan arum (Amorphophallus titanum). It should not be confused with Dioscorea species, which are also known by the common name yam, but belong to a different plant family (Dioscoreaceae). In particular it should not be confused with elephant's foot yam (Dioscorea elephantipes) from South Africa.

Elephant yam has medicinal properties and is used in many Ayurvedic (traditional Hindu) preparations. The tubers are considered to have pain-killing, anti-inflammatory, anti-flatulence, digestive, aphrodisiac, rejuvenating and tonic properties. They are traditionally used in the treatment of a wide range of conditions including parasitic worms, inflammation, coughs, flatulence, constipation, anaemia, haemorrhoids and fatigue.

Further research is needed to determine the pharmacological properties of elephant yam.

Species Profile

Geography and distribution

Amorphophallus paeoniifolius is considered to be native to southern China (including Taiwan), Bangladesh, India, Sri Lanka, Laos, Burma, Thailand, Vietnam, Borneo, Java, Peninsular Malaysia, Philippines, Sulawesi, Sumatra, New Guinea, northern Australia, Fiji and Samoa.

It is found in secondary forest or highly disturbed areas, up to 800 m above sea level.

It is considered naturalised in Madagascar and the Seychelles.

Elephant yam has been in cultivation throughout tropical Asia for centuries. It has been widely transported by humans and easily escapes from cultivation to become naturalised, so that its natural distribution is not clear.

Description

Overview: Perennial herb. A single inflorescence (flowering structure) is produced, followed by a solitary leaf. After the growing season, this dies back to an underground storage organ (tuber).

Tuber (thickened part of underground stem): Dark brown, flattened-globe-shaped, up to 50 × 30 cm with prominent root scars. Weighing up to about 15 kg.

Leaves: Usually one (sometimes two) per tuber. Petiole (leaf stalk) up to 2 m tall and 20 cm in diameter with rough, warty surface. Background colour pale to dark green or blackish-green with pale blotches and numerous tiny dark dots. Leaf blade up to 3 m in diameter and deeply divided into segments. Leaflets up to 35 × 12 cm.

Spadix (flower spike): Up to 70 cm long. The lowermost portion of the spadix is female and is covered with pistils (female parts). Each pistil consists of a pale green or maroon ovary with a maroon stalk (style) and two- or three-lobed yellow head (stigma). The next floral zone is male and contains tightly-packed yellowish stamens. At the tip of the spadix is a bulbous, dark maroon, rounded to deeply wrinkled appendix.

Spathe (bract surrounding spadix): Bell-shaped, broader than long, up to 45 × 60 cm, pale green to dark brown with paler blotches on exterior. Opening outwards to form a frilled, glossy maroon, collar-like structure around the spadix. Basal portion of interior pale green-yellow.

Fruits: About 2 × 1 cm, bright red when ripe. Borne on a spike up to 50 cm long and 8 cm in diameter, the fruiting part held aloft on a peduncle (stalk) 20-100 cm long.

The flower spike (spadix) emits an odour reminiscent of rotting flesh, which attracts pollinators such as carrion flies and beetles.

Uses

Elephant yam is widely cultivated for its edible tubers, which are an important source of carbohydrate in India and Indonesia and a valued secondary crop throughout tropical Asia. It can be found on sale further afield (including Hounslow, not far from Kew in the UK) in international food markets.

It is also widely used as fodder.

Elephant yam is cultivated as an ornamental for its striking compound foliage and unusual and dramatic flowering and fruiting structures.

This species at Kew

Elephant yam can be seen growing in the Tropical Carnivorous Zone (Zone 8) of the Princess of Wales Conservatory at Kew.

This newly redeveloped zone is home to many other species including Nepenthes truncata , N. rafflesiana , N. veitchii , N. bicalcarata and the recently described N. robcantleyi . The zone also features voodoo lily ( Amorphophallus variabilis ) and a new hybrid at Kew A. decus-silvae × gigas , plus a range of epiphytic ferns and orchids including Bulbophyllum species.

Dried and alcohol-preserved specimens of Amorphophallus paeoniifolius are held in Kew's Herbarium. The details, including images, of some of these can be seen online in Kew's Herbarium Catalogue.

Distribution

Australia, China, India, Laos, Philippines, Taiwan, Thailand, Vietnam

Ecology

Secondary forest or highly disturbed areas.

Conservation

Not considered to be threatened.

Hazards

Tubers of wild plants are highly acrid and can irritate the mouth and throat on ingestion due to the presence of calcium oxalate crystals.

Use

Is cultivated in many parts of the Old World Tropics for its massive starchy tuber.

Use

Food, fodder, medicine.