Description from Flora of China
Malus domestica Borkhausen var. micromalus (Makino) Likhonos; M. microcarpa A. Savatier var. kaido (Siebold) Carrière; M. spectabilis Borkhausen var. kaido Siebold; M. spectabilis var. micromalus (Makino) Koidzumi; Pyrus micromalus (Makino) Makino.
Trees small, to 2.5–5 m tall. Branchlets purplish brown or dark brown, terete, slender, puberulous when young, glabrescent; buds dark purple, ovoid, glabrous, or scales tomentose at margin. Stipules caducous, linear-lanceolate, 4–6 mm, membranous, subglabrous, margin sparsely glandular denticulate, apex acuminate; petiole 2–3.5 cm, pubescent when young, glabrescent; leaf blade narrowly elliptic or elliptic, 5–10 × 2.5–5 cm, puberulous when young, glabrescent, base cuneate, rarely subrounded, margin serrate, apex acute or acuminate. Corymb umbel-like, 4–6 cm in diam., 4–7-flowered; bracts caducous, linear-lanceolate, membranous, margin entire, apex acuminate. Pedicel 2–3 cm, villous when young, glabrescent. Flowers ca. 4 mm in diam. Hypanthium white tomentose abaxially. Sepals triangular-ovate or triangular-lanceolate, 5–8 mm, ca. as long as or slightly shorter than hypanthium, abaxially pubescent, adaxially white tomentose, margin entire, apex acute or shortly acuminate. Petals pink, suborbicular or narrowly elliptic, ca. 1.5 cm, base shortly clawed, apex rounded. Stamens ca. 20, unequal, slightly shorter than petals. Styles 5, ca. as long as stamens, tomentose basally. Pome red, subglobose, 1–1.5 cm in diam.; impressed at apex, with cavity at base; fruiting pedicel 2–3 cm, subglabrous; sepals caducous or a few persistent. Fl. Apr–May, fr. Aug–Sep. 2n = 34*, 51*.
According to Bean (Trees Shrubs Hardy Brit. Isles, ed. 8, 2: 710), this taxon is a hybrid between Malus spectabilis and probably M. baccata.
In N China, this taxon is usually planted in gardens and parks for ornamental purposes and for its edible fruit. It is used as stock to graft Malus asiatica and M. pumila in some regions.
It is unknown if M. spectabilis var. micromalus (Makino) Koidzumi is validly published. If the Tokyo Herbarium had distributed specimens with printed labels showing the name “Malus spectabilis var. micromalus (Makino) Koidzumi;” the name would be valid.
Also, if any Chinese or Japanese work, published before 1953, listed the name “Malus spectabilis var. micromalus (Makino) Koidzumi” as an accepted name, then it would be a valid name. From 1953, an acceptance + full basionym citation are needed for validity.
Commonly cultivated. Gansu, Guizhou, Hebei, Liaoning, Nei Mongol, Shaanxi, Shandong, Shanxi, Yunnan, Zhejiang.