Alocasia macrorrhizos (L.) G.Don

Pachycaul herbs, massive, to 4 m, evergreen, latex slightly milky. Stem erect, to ca. 1.5 m, decumbent. Leaves several together, clustered at tips of stems in larger plants; petiole to 1.3 m, sheathing in proximal 1/3-1/2; leaf blade light green on both surfaces, ovate-sagittate, bluntly triangular, up to 120 × 50 cm, ± erect, margin entire to very slightly sinuous; posterior lobes 1/3-1/2 length of anterior, somewhat rotund, often overlapping, naked in sinus in mature plants, weakly peltate in juveniles; primary lateral veins ca. 9 on each side of anterior lobe, axillary glands distinct, secondary venation not forming interprimary collective veins. Inflorescences paired among leaf bases, subtended by membranous cataphylls; peduncle barely exceeding cataphylls at anthesis. Spathe 13-35 cm, constricted ca. 1/6 from base; proximal spathe green, ovoid; limb cowl-like at anthesis, later reflexed, then deliquescent, pale yellow, broadly oblong-lanceolate, 10.5-29 cm. Spadix slightly shorter than spathe, shortly stipitate; female zone conic-cylindric, 1-2 × ca. 1.5 cm; pistil pale green, ca. 3 mm in diam.; stigma yellow, sessile, 3-5-lobed; sterile zone slightly equaling female zone, whitish; synandrodes rhombic-hexagonal, ca. 2.5 mm in diam.; male zone whitish, cylindric, 3-7 × ca. 2 cm; synandria 5-9-merous, rhombic-hexagonal, convex-topped, ca. 2 mm in diam.; appendix yellowish, slightly tapering, at least 1/2 length of spadix. Fruiting spathe green, oblong-ellipsoid, ca. 8 cm. Fruit ripening scarlet, ellipsoid, ca. 12 × 8 mm.

A tropical plant. It is widely distributed in open wetlands and along streams and in some types of humid forest. The plant grows wild from sea level up to 2600 m altitude in the tropics. Giant taro is a tropical plant and will not grow well below 10°C. It requires a well distributed rainfall and does not tolerate drought. Even though it grows along creek banks it cannot tolerate waterlogged soil. It is only used as food in a few coastal areas. Wild forms commonly seen growing are bitter and not used. It does not do well on atolls. It suits hardiness zones 11-12.

The stems and corms are eaten after roasting or boiling. The main corm is cooked and eaten after being carefully peeled. The young leaves are edible. CAUTION The mouth can be irritated by chewing improperly cooked plant parts due to chemicals called oxalates. The stems are cut into small pieces and boiled and eaten in curries. The stems are boiled and the water thrown away. The starch is also extracted from the rootstocks. The young shoots are cooked and eaten. The harvested food can be stored for about one week.

The top of the main corm is planted. The small round cormels can be planted, but are slow to mature. A spacing of 1.2 x 1.2 m is suitable. Because the giant taro takes more than a year to be ready to harvest, it often ends up left growing in an old garden site without much care or weeding, until the owner wants to harvest it. The mouth can be irritated by chewing improperly cooked plant parts due to chemicals called oxalates. Giant taro contains small needle-like calcium oxalate crystals in the tissues. It is necessary to remove these during the preparation and cooking. The method of peeling is important. Normally some ladies who are especially experienced at peeling do this job. Also the taro corm is often left to wilt for a week after it is harvested and before it is used. Also to help remove some of the crystals, the stem is baked for a long time, or boiled in several changes of water. It is also important to use the right variety of giant taro because the kinds grown in gardens have less of the chemical than wild ones.