Description from Flora of China
Pyrus sieversii Ledebour, Fl. Altaic. 2: 222. 1830.
Trees 2–10(–14) m tall; branchlets dark grayish red when old, terete, short, robust, puberulous when young, slightly curved, glabrescent when old; buds dark red, ovoid, villous abaxially. Stipules caducous, lanceolate, 3–5 mm, membranous, margin white ciliate, apex acuminate; petiole 1.2–3.5 cm, sparsely pubescent; leaf blade ovate or broadly elliptic, rarely obovate, 6–11 × 3–5.5 cm, abaxially densely villous when young, sparsely pubescent when old, adaxially sparsely pubescent along veins, base cuneate, rarely rounded, margin obtusely serrate, apex acute. Corymb umbel-like, 4–6 cm in diam., 3–6-flowered; bracts caducous, lanceolate, membranous, margin glandular serrate when young, apex acuminate. Pedicel ca. 1.5 cm, white tomentose. Flowers 3–3.5 cm in diam. Hypanthium campanulate, abaxially tomentose. Sepals broadly lanceolate or triangular-lanceolate, ca. 6 mm, longer than hypanthium, both surfaces tomentose, margin entire, apex acuminate. Petals pinkish, tinged rose when in bud, obovate, 1.5–2 cm, base shortly clawed, apex rounded. Stamens 20, unequal, ca. 1/2 as long as petals. Ovary 5-loculed, with 2 ovules per locule; styles 5, ca. as long as or slightly longer than stamens, white tomentose basally. Pome yellowish green, tinged red, globose or depressed-globose, 3–4.5(–7) cm in diam.; fruiting pedicel 3.5–4 cm, white tomentose; sepals persistent, reflexed; with cavity at apex. Fl. May, fr. Aug–Oct. 2n = 34*.
This species is vulnerable to extinction because of its limited range and exploitation. It is believed to be the principal ancestor of commercially grown apples.
Mountain summits, slopes, valleys, often the dominant tree of forests; 1200--1300 m. W Xinjiang [Kazakhstan, Russia].