Malus sylvestris found that current populations of "M. pumila" are more closely related to "M. sylvestris" than to "M. sieversii". However, in more pure strains of "M. pumila" the "M. sieversii" ancestry still predominates. The flowers are hermaphrodite and are pollinated by insects. Its leaves are food of the caterpillars of the twin-spotted sphinx ("Smerinthus jamaicensis") and possibly the hawthorn moth ("Scythropia crataegella"). Malus sylvestris Malus sylvestris, the European crab apple, is a species of the genus "Malus", native to Europe. Its scientific name means "forest apple" and the truly wild tree has thorns. Wild apple has an expanded crown and often
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