木薯 mu shu

Jatropha manihot Linnaeus, Sp. Pl. 2: 1007. 1753; Janipha aipi (Pohl) J. Presl; J. manihot (Linnaeus) Kunth; Jatropha stipulata Vellozo; Mandioca aipi (Pohl) Link; M. dulcis Parodi; M. utilissima (Pohl) Link; Manihot aipi Pohl; M. edulis A. Richard; M. utilissima Pohl.

Erect shrubs 1.5-5 m tall; root tubers terete. Stipules triangular-lanceolate, 5-7 mm, entire or with 1 or 2 bristly segments; petiole 6-35 cm, slightly peltate, inserted less than 5 mm from margin; leaf blade palmately 3-9-lobed, 5-20 cm, lobes oblanceolate to narrowly elliptic, 8-18 × 1.5-4 cm, apex acu-minate, entire; lateral veins 5-15. Racemes terminal or axillary, 5-8 cm; bracts oblong-lanceolate; pedicels 4-6 mm. Male flowers: calyx ca. 7 mm, purple-red, divided to or over middle, lobes long ovate, 3-4 × ca. 2.5 mm, hairy inside; stamens 6-7 mm; anthers white pubescent at apex. Female flowers: calyx ca. 10 mm, lobes oblong-lanceolate, ca. 8 × 3 mm; ovary ovoid, longitudinally 6-angled; stigmas recurved, plaited. Capsule ellipsoidal, 1.5-1.8 × 1-1.5 cm, longitudinally 6-winged, scabrous. Seeds slightly triangular, ca. 1 cm; testa crustaceous, smooth, with spot-stripes. Fl. Sep-Nov.

Widely cultivated. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Taiwan, Yunnan [native to Brazil; cultivated throughout the tropics].

The root tubers yield tapioca and are a staple crop in many areas of the tropics. They contain hydrocyanic acid and may cause death if eaten raw; they become edible after thorough soaking in water and cooking.