Malus sylvestris to most European countries. It occurs in a scattered distribution pattern as single individuals or in small groups. In the past "M. sylvestris" was thought to be the most important ancestor of the cultivated apple ("M. pumila"), which has since been shown to have been originally derived from the central Asian species "M. sieversii". However another recent DNA analysis confirms that "M. sylvestris" has contributed significantly to the genome. The study found that secondary introgression from other species of the genus "Malus" has greatly shaped the genome of "M. pumila", with "M. sylvestris" being the largest secondary contributor. It also
Malus are borne in corymbs, and have five petals, which may be white, pink or red, and are perfect, with usually red stamens that produce copious pollen, and a half-inferior ovary; flowering occurs in the spring after 50–80 growing degree days (varying greatly according to subspecies and cultivar). Apples require cross-pollination between individuals by insects (typically bees, which freely visit the flowers for both nectar and pollen); all are self-sterile, and (with the exception of a few specially developed cultivars) self-pollination is impossible, making pollinating insects essential. Several "Malus" species, including domestic apples, hybridize freely. They are used as food plants