Several cultivars of this small Central Asian tree ("Siberian crab-apple") have become extensively planted across North America in recent decades. Self-sown escapes are becoming widely scattered across Ky., much more so than indicated by the few colls. mapped here. However, dense invasive ppulations are unknown in the state. Twigs and leaves (all unlobed) are largely glabrous, or slightly puberulent on lower leaf surfaces when young; fruits are usually medium-sized (ca. 8-10 mm) with deciduous calyx. The horticultural micro-taxonomy of these plants is complex (CW), with much variation in flower color, fruit color and other characters. However, only diploids are generally recorded (2n = 34). In other horticultural Eurasian species of Malus, there are varied chromosome numbers (Gu C-Z & S.A. Sponberg in Flora of China 9). Occasional hybrids of baccata with pumila / domestica may be expected (Korban 1986, Cronin et al. 2021) and are suspected in Ky. A related East Asian species. M. floribunda Sieb. ex Van Houtte (= M. halliana Koehne or "Japanese crab"), is also expected (K, W)). It has sepal lobes triangular-ovate, 3-5 mm long (versus lanceolate, 5-7 mm), equalling or shorter than the calyx tube (versus longer); anthers white (versus yellow); fruits oblong or pyriform, dark red or purple (versus subglobose, yellow to red).