This is the common cultivated apple; nomenclature has been confused but may now be resolved (FNA 9, W); 2n = 34 or rarely 51 or 68. M. domestica is widely reported as escaped across North America but less frequently in warmer or drier regions, including s. Ky. and further south or west (K). There has been confusion in nomenclatuew with typical M. sylvestris P. Mill. (the wild European crab apple), which is not verified from Kentucky (M). Although sylvestris has contributed to the germplasm of domestica, the major original source appears to be M. sieversii (Ldb.) Roem of central Asia (Cornille et al. 2014). M. domestica differs from sylvestris as follows (Clapham et al. 1962): twigs rarely thorny (versus usually thorny), tomentose at first but later glabrous (versus glabrous or loosely hairy when young); buds hairy (versus glabrous or hairy when young); leaves obtuse to acuminate (versus acuminate or cuspidate), more or less persistently pubescent beneath (versus sparingly hairy on veins of both sides when young and soon glabrous); pericels, receptacle and outside of calyx tomentose (versus glabrous or nearly so); fruits usually mostly 2.5-10 cm wide, becoming sweet (versus 2-2.5 cm, remaining sour). Pollen from domestica may rarely hybridize with native apples or may result in increased apomixis of tetraploid embryos in coronaria (Sargent 1926; Cr, FNA 9; Kron & Husband 2009, Cronin et al. 2020, Greaves 2022). Among the many cultivars, "Hopa Crab" and its allies are remarkable due to the red flesh of their relatively small fruits. These trees are derived in part from M. niedzwetskyana Dieck ex Koehne of Central Asia, a species that has sometimes been combined with domestica.