11. Ipomoea batatas (Linnaeus) Lamarck, Encycl. 2: 465. 1793.
番薯 fan shu
Convolvulus batatas Linnaeus, Sp. Pl. 1: 154. 1753; Batatas edulis (Thunberg ex Murray) Choisy; C. candicans Solander ex Sims; C. edulis Thunberg ex Murray; Ipomoea batatas var. edulis (Thunberg ex Murray) Makino; I. batatas var. lobata Gagnepain & Courchet; I. edulis (Thunberg ex Murray) Makino; I. fastigiata Sweet.
Herbs annual, with ellipsoid, fusiform, or elongated subterranean tubers; sap milky; axial parts glabrous or pilose. Stems prostrate or ascending, rarely twining, green or purplish, much branched, rooting at nodes. Petiole 2.5-20 cm; leaf blade broadly ovate to circular, 4-13 X 3-13 cm, margin entire or palmately 3-5(-7)-lobed, herbaceous; lobes broadly ovate to linear-lanceolate, sparsely pilose or glabrous. Inflorescences 1- or 3-7-flowered; peduncle 2-10.5 cm, stout, angular; bracts early deciduous, lanceolate, 2-4 mm. Pedicel 2-10 mm. Sepals oblong or elliptic, ± unequal, glabrous or pilose abaxially, margin ciliate, apex acute, mucronulate, outer 2 sepals 7-10 mm, inner 3 sepals 8-11 mm. Corolla pink, white, pale purple to purple, with a darker center, campanulate to funnelform, 3-4 cm, glabrous. Stamens included. Pistil included; ovary pubescent or glabrous. Capsule rarely produced, ovoid or depressed globose. Seeds glabrous. 2n = 84, 90*.
Cultivated throughout China, sometimes persisting from cultivation, but doubtfully naturalized [Indonesia, Japan (Ryukyu Islands), Laos, Malaysia, Nepal, New Guinea, Pakistan, Philippines, Sri Lanka, Thailand, Vietnam; Africa, Australia, North America, Pacific Islands, South America, cultivated worldwide]
Ipomoea batatas is a productive and adaptable crop. Its tubers are an important source of food, starch, and raw material for producing alcohol. The stems and leaves can be used as livestock forage. In ancient Chinese texts, the name now used for "sweet potato" refers to Dioscorea alata Linnaeus, and not this species.