Crabapple

Apple trees are small, typically 4–12 m tall at maturity, with a dense, twiggy crown. 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. The honeybee and mason bee are the most effective[citation needed] insect pollinators of apples. Malus species, including domestic apples, hybridize freely. Malus species are used as food plants by the larvae of a large number of Lepidoptera species; see list of Lepidoptera that feed on Malus.
Hybrid Crabapple grown for its flowering.
The fruit is a globose pome, varying in size from 1–4 cm diameter in most of the wild species, to 6 cm in M. sylvestris sieversii, 8 cm in M. sylvestris domestica, and even larger in certain cultivated orchard apples; among the largest-fruited cultivars (all of which originate in North America) are 'Wolf River' and 'Stark Jumbo' . The centre of the fruit contains five carpels arranged star-like, each containing one to two (rarely three) seeds.