1. Alocasia (Schott) G.Don, Hort. Brit., ed. 3: 631 (1839).
By: Nawal Shrestha & Krishna K. Shrestha
Taxon Description
Perennial, medium-sized (rarely gigantic) herbs, bearing latex. Stems thick, often subterranean, sometimes stoloniferous and bulbiferous, above-ground stem usually erect and later prostrate. Leaves few to many in terminal crown, less frequently scattered, growing on long petioles, occasionally with a cataphyll subtending each leaf; leaf blade occasionally pubescent on the underside, juvenile blade peltate, mature blade usually sagittate or cordate, margin entire or sinuate; wax glands present in axils of primary lateral veins and midrib. Inflorescences 1 or 2 to many, peduncle shorter than petioles. Spathe erect, convolute, deeply narrowed between tube and blade; tube shorter than limb, ovoid or oblong, margin convolute; limb oblong, usually boat-shaped. Spadix sessile, occasionally with short stipes, shorter than spathe, female zone conic-cylindric, short, separated from male zone by a narrow neuter zone, male zone cylindric. Spadix appendix conic to cylindric, with irregular clefts. Flowers unisexual, naked. Fruit berry, red, ellipsoid or sub-globose, odorless. Seeds subglobose to ellipsoid.
Taxon Statistics
Worldwide 90 species, native to tropical and subtropical Asia and eastern Australia. Three species in Nepal.
Key to Species
1a Plants growing to more than 2 m. Stems with caudex. Spadix as long as spathe ………..…. 2. A. macrorrhizos
b Plants growing to less than 2 m. Stems without caudex. Spadix shorter than spathe …………………………….….. 2
2a Plants pachycaul. Leaf blade cordate-ovate, ca. 130 X 120 cm ………………………………………….. 3. A. navicularis
b Plants leptocaul. Leaf blade cordate or sagittate, ca. 100 X 80 cm …………………………………….…… 1. A. fornicata
1. Alocasia fornicata (Kunth) Schott, Oesterr. Bot. Wochenbl. 4: 410 (1854).
Colocasia fornicata Kunth, Enum. Pl. 3: 41 (1841); Arum fornicatum Roxb, Fl. Ind., ed.
- 3: 501 (1832).
Perennial herbs up to ca. 150 cm. Stems erect or decumbent. Leaves several, clustered together at stem tip, petioles dull purple with membranous petiolar sheath, ca. 1.5 m; leaf blade peltate, ca. 100 X 80 cm, margin entire, base cordate or sagittate, apex short acuminate; lateral veins 9–12 on each side. Peduncles dull purple, stout, shorter than or as long as petiole, ca. 45 cm. Spathe constricted roughly one-sixth of the way from the base, grayish green, slightly glaucous, 10–12 cm; limb broadly oblong-lanceolate, apex cuspidate. Spadix shorter than spathe, shortly stipitate, female zone 1–2 cm, neuter zone narrowing abruptly above the female zone, male zone ca. 3–5 cm; appendix white, elongate-conical, as long as spadix, gradually tapering, 3–5.5 X 1–2 cm.Distribution: Nepal, E Himalaya, Assam-Burma, S Asia and SE Asia.
Altitudinal range: 100–300 m.
Ecology: In marshy and shady place.
Flowering: April–June. Fruiting: April–June.
2. Alocasia macrorrhizos (L.) G.Don, Hort. Brit. (ed. 3) :631 (1839).
Arum macrorrhizon L., Sp. Pl. 2: 965 (1753).
घ्याम्पे तरुल (Ghyampe tarul); जाँते तरुल (Jante tarul).
Giant perennial herbs up to 4 m. Stems erect, with caudex. Leaves 2–4, petioles 60–120 cm, longer than or equal to length of blade; leaf blade ovate, obtuse or subacute, ca. 120 X 50 cm, margin entire, base deeply sagittate or cordate, apex short acuminate; lateral veins 10–12 on each side. Peduncles pale green, stout, shorter than petiole, 15–20 cm. Spathe green, 15–25 cm; limb oblong-lanceolate, hooded, apex cuspidate. Spadix light greenish yellow, almost as long as spathe, emitting unpleasant odor, female zone 1–2 cm, neuter zone equaling female zone, male zone 3–7 cm; appendix yellow, cylindric, almost as long as spadix, sinuously grooved, 10–15 cm.
Distribution: Native of SE Asia; Australasia. Naturalized in Nepal.
Altitudinal range: 700–1000 m.
Ecology: Shady areas of wastelands and farmlands.
Flowering: May–June. Fruiting: May–June.
3. Alocasia navicularis (K.Koch & C.D.Bouché) K Koch & C.D.Bouché, Index Seminum 2 (1855).
Colocasia navicularis K.Koch & C.D.Bouché, Index Seminum 13. (1853).
पिँडालु (Pindalu), माने (Mane).
Large pachycaul perennial herbs up to ca. 150 cm. Stems erect to decumbent. Leaves several, clustered together at stem tip, petioles up to ca. 1.5 m with membranous petiolar sheath; leaf blade peltate, ca. 130 X 120 cm, margin entire, base cordate-ovate, apex short acuminate; lateral veins 9–12 on each side. Peduncles pale green, stout, shorter than petiole, 40–45 cm. Spathe constricted roughly one-sixth of the way from the base, green, 10–20 cm; limb dark yellow, oblong-lanceolate, apex cuspidate. Spadix shorter than spathe, shortly stipitate, female zone pale green, 1–2 cm, neuter zone equaling male zone, narrowed corresponding to spathe constriction, male zone 3–4 cm; appendix white, elongate-conical, as long as spadix, 3–4 X 1–2 cm.
Distribution: Nepal, Assam-Burma, S. Asia, E Asia and SE Asia.
Altitudinal range: 400–500 m.
Ecology: Moist evergreen montane forests.
Flowering: April–May. Fruiting: May–June.
A wide variety of hybrids and cultivars of Alocasia are grown around the world as ornamentals. Although corms of some species can be processed to make them palatable, the raw plants contain raphide crystals of calcium oxalate, as well as various irritants, which can numb and swell the tongue and pharynx. It is crucial to remember that the toxicity of Alocasia varies, and it can still be deadly to consume even after processing.