15. Malus sieboldii (Regel) Rehder in Sargent, Pl. Wilson. 2: 293. 1915.
三叶海棠 san ye hai tang
Pyrus sieboldii Regel, Index Sem. Hort. Petrop. 1858: 51. 1859; Crataegus cavaleriei H. Léveillé & Vaniot; C. taquetii H. Léveillé; Malus baccata (Linnaeus) Borkhausen subsp. toringo (K. Koch) Koidzumi; M. sieboldii (Regel) Rehder var. toringo (K. Koch) Siebold ex C. K. Schneider; M. toringo (K. Koch) Carrière; Photinia rubrolutea H. Léveillé; Pyrus esquirolii H. Léveillé; P. subcrataegifolia H. Léveillé; P. toringo (K. Koch) Miquel; Sorbus toringo K. Koch.
Shrubs 2–6 m tall. Branchlets spreading, dark purple or purplish brown, terete, puberulous when young, glabrescent; buds purplish brown, ovoid, glabrous or only terminal scales puberulous at margin. Stipules narrowly lanceolate, 4–6 mm, herbaceous, slightly puberulous, margin entire, apex acuminate; petiole 1–2.5 cm, puberulous; leaf blade ovate, elliptic, or narrowly elliptic, 3–7.5 × 2–4 cm, both surfaces puberulous when young, abaxially puberulous along midvein and lateral veins when old, adaxially subglabrous, base rounded or broad cuneate, margin serrate, often 3-lobed, rarely 5-lobed on new branches, apex acute. Corymb at apices of branchlets, 4–6 cm in diam.; 4–8-flowered; bracts caducous, linear-lanceolate, membranous, adaxially pubescent, margin entire, apex acuminate. Pedicel 2–2.5 cm, pubescent or subglabrous. Flowers 2–3 cm in diam. Hypanthium campanulate, subglabrous or pubescent. Sepals ca. as long as or slightly longer than hypanthium, abaxially glabrous, adaxially tomentose, margin entire, apex caudate-acuminate. Petals pinkish, elliptic-obovate, 1.5–1.8 cm, base shortly clawed, apex rounded. Stamens 20, unequal, ca. 1/2 as long as petals. Ovary 3–5-loculed, with 2 ovules per locule; styles 3–5, slightly longer than stamens, villous basally. Pome red or brownish yellow, subglobose, 6–8 mm in diam.; sepals caducous; fruiting pedicel 2–3 cm. Fl. Apr–May, fr. Aug–Sep. 2n = 34*, 51*.
Mixed forests, among shrubs, slopes; 150--2000 m. Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Liaoning, Shaanxi, Shandong, Sichuan, Zhejiang [Korea, Japan].
This species can be used as an ornamental tree for its showy flowers in the spring. In Liaoning and Shandong provinces, it is sometimes used as stock for grafting apple trees.