芋 yu

Arum esculentum Linnaeus, Sp. Pl. 2: 965. 1753; A. colocasia Linnaeus; Caladium colocasia (Linnaeus) W. Wight; C. esculentum (Linnaeus) Ventenat; Calla gaby Blanco; Colocasia antiquorum Schott var. esculenta (Linnaeus) Schott ex Seemann; C. formosana Hayata; C. konishii Hayata; C. neocaledonica Van Houtte.

Rhizome vertical to horizontal, tuberous, 3-5 cm or more (up to 15 cm) in diam. Stolons long or absent. Leaves 2 or 3 or more; petiole green, 25-80 cm, sheathing for 1/3-2/3 length; leaf blade adaxially matte waxy-glaucous and water-shedding (water sometimes forming "mercury droplets"), oblong-ovate to suborbicular, 13-45 × 10-35 cm, base shallowly cordate (sinus 1-4 cm), apex broadly and shortly cuspidate. Peduncle usually solitary, 16-26 cm. Spathe tube green, 3.5-5 × 1.2-1.5 cm; limb open proximally, cream-colored to golden yellow, lanceolate or elliptic, 10-19 × 2-5 cm, apex acuminate. Spadix: female zone conic, 3-3.5 × ca. 1.2 cm; ovary 1-3 mm in diam.; stigma subsessile, narrower than apex of ovary; sterile zone narrowly cylindric, 3-3.3 cm; sterile flowers (pistils) seen from above elongate, ca. 0.5 mm in diam.; male zone cylindric, 4-6.5 cm × ca. 7 mm; appendix narrowly conic, 15-45 × ca. 2 mm. Berry green, ca. 4 mm. Seeds few; synandria ca. 1 mm high, ca. 0.8 mm in diam. Fl. Feb-Apr (Yunnan), or Aug-Sep (Qin Ling area). 2n = 26, 28, 30, 36, 38, 42, 44, 46, 48, 52, 58, 84, 116.

Widely cultivated usually near farmhouses or in water fields; also naturalized or perhaps native in wet places in forests, valleys, swamps, wastelands, and at watersides. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [widely cultivated in tropics and subtropics].

This very variable species is widely cultivated throughout the tropics, and many wild or naturalized clones are found in S Asia, Malesia, and the Pacific islands. The spathes, spadices, and spadix appendixes vary considerably, although the floral organs have not been observed in many cultivated clones. This wide variation is attributable to cultivation selections, escapes, naturalizations, and re-domestications. It seems best, therefore, to treat Colocasia esculenta as a single species rather than formally recognize infraspecific taxa or segregate species (see Hay, Sandakania 7: 31-48. 1996).

The rhizomes, petioles, and inflorescences are used as a vegetable. The rhizomes are used medicinally for treating swellings, abscesses, snake and insect bites, and swollen lymph nodes in the neck.