Description
Apple trees are typically 4–12 m (13–39 ft) talI at maturity, with a dense, twiggy crown. The leaves are 3–10 cm (1.2–3.9 in) long, alternate, simple, with a serrated margin. The flowers 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).
Many apples require cross-pollination between individuals by insects (typically bees, which freely visit the flowers for both nectar and pollen); these are called self-sterile, so self-pollination is impossible, making pollinating insects essential.
A number of cultivars are self-pollinating, such as 'Granny Smith' and 'Golden Delicious', but are considerably fewer in number compared to their cross-pollination dependent counterparts.
Several Malus species, including domestic apples, hybridize freely. They are used as food plants by the larvae of a large number of Lepidoptera species; see list of Lepidoptera that feed on Malus.
The fruit is a globose pome, varying in size from 1–4 cm (0.39–1.57 in) diameter in most of the wild species, to 6 cm (2.4 in) in M. sylvestris sieversii, 8 cm (3.1 in) in M. domestica, and even larger in certain cultivated orchard apples. The centre of the fruit contains five carpels arranged star-like, each containing one or two seeds.
Culinary uses
Crabapple fruit is not an important crop in most areas, being extremely sour due to malic acid (which like the genus derives from the Latin name mālum), and in some species woody, so is rarely eaten raw. In some Southeast Asian cultures, they are valued as a sour condiment, sometimes eaten with salt and chilli or shrimp paste.[citation needed]
Some crabapple varieties are an exception to the reputation of being sour, and can be very sweet, such as the 'Chestnut' cultivar.
Crabapples are an excellent source of pectin, and their juice can be made into a ruby-coloured preserve with a full, spicy flavour. A small percentage of crabapples in cider makes a more interesting flavour. As Old English Wergulu, the crab apple is one of the nine plants invoked in the pagan Anglo-Saxon Nine Herbs Charm, recorded in the 10th century.
Applewood gives off a pleasant scent when burned, and smoke from an applewood fire gives an excellent flavour to smoked foods. It is easier to cut when green; dry applewood is exceedingly difficult to carve by hand. It is a good wood for cooking fires because it burns hot and slow, without producing much flame.
