海芋 hai yu

Arum odorum Roxburgh, Fl. Ind., ed. 1832, 3: 499. 1832; Alocasia commutata Schott; A. tonkinensis Engler; Arum odoratum Heynhold; Caladium odoratissimum K. Koch; C. odoratum Ker Gawler (1822), not Loddiges (1820); Colocasia odora (Roxburgh) Brongniart.

Pachycaul herbs, massive, to 2.5 m, evergreen, with slightly milky latex. Stem erect to decumbent, with short stolons terminating in tubercles arising from base. Leaves several to rather many together, clustered at tips of stems of larger plants; petiole up to 1.5 m, sheath membranous; leaf blade peltate, cordate-sagittate or cordate-ovate, up to 130 × 100 cm, basal margins undulate, apex shortly acuminate; primary lateral veins 9-12 on each side, interprimary veins forming well-defined interprimary collective veins. Inflorescences 2 or 3 together among leaf bases, subtended by membranous cataphylls; peduncle stout, ca. 35 cm, exceeding cataphylls at anthesis. Spathe 13-25 cm, constricted ca. 1/6 of way from base; proximal part green, ovoid; limb cowl-like at anthesis, later reflexed, then deliquescent, greenish white, broadly oblong-lanceolate, 10-30 × 4-8 cm, membranous. Spadix shorter than spathe, shortly stipitate; female zone 1-2 × ca. 1.5 cm; pistil pale green, ca. 3 mm in diam.; stigma sessile, weakly 3-lobed, lobes blunt, pale green; sterile zone equaling male zone, ivory, very slightly narrowed corresponding to spathe constriction; synandrodes rhombic-hexagonal, ca. 2.5 mm in diam.; male zone whitish, cylindric, 3-5 × ca. 2 cm; synandria rhombic-hexagonal, convex-topped due to cap-forming synconnective, ca. 1.5 mm in diam.; appendix white, narrowly conic, 3-5.5 × 1-2 cm, equaling ca. 1/3 length of spadix, markedly thicker than male zone at base, slowly tapering toward apex. Fruiting spathe ca. 6 cm. Fruit ripening scarlet, globose, ca. 1 cm in diam.

Primary and secondary tropical rain forests, bamboo thickets, riverbanks, swamps, also on limestone; below 1700 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangxi, Sichuan, Taiwan, Yunnan [Bangladesh, Bhutan, Cambodia, NE India (Assam), Japan (Ryukyu Islands), Laos, Myanmar, Nepal, Thailand].

Alocasia odora differs from A. macrorrhizos in having shortly peltate leaves (vs. deeply cordate at the base with the lateral lobes partially naked in the sinus in A. macrorrhizos).

The rhizomes are used for treating stomach aches, abdominal pains, cholera, and hernias, and are used externally to treat abscesses and snake and insect bites.