The flowers of apple trees are white and flushed, with a diameter of 3 ~ 5 cm. Pedicels and calyx have gray hairs, calyx leaves are long and persistent, with 20 stamens and 5 styles. Most varieties are self-sterile, so pollination trees need to be planted. The fruit is slightly oblate, more than 5 cm in diameter, with concave ends and often ribbed ends.

The flower buds of apples are mixed buds. Axillary flower buds are buds formed in the axils of leaves of branches of the same year, and those that can blossom and bear fruit in the next year are called axillary flower buds. The flower bud differentiation of apple began in early June and ended before winter, and the inflorescence was corymbose cymes. 5-7 flowers per inflorescence.

Most apple trees are cross-pollinated, and 2 ~ 4% of apple trees have ideal fruit setting. Although the size, shape, color and acidity of mature apples vary greatly with varieties and environmental conditions, they are generally round, with a diameter of 50 ~ 100 mm and a reddish or yellowish color.

Extended data:

Apple tree is a temperate fruit tree that likes low temperature and dryness. It requires no cold in winter and no heat in summer. The suitable temperature range is the annual average temperature of 9 ~ 14℃, the extreme low temperature in winter is not lower than-12℃, and the highest monthly average temperature in summer is not higher than 20℃.

In the growing season (April ~ 65438+1October), the average temperature is 12 ~ 18℃, and it takes 1200 ~ 1500 hours to successfully pass the natural dormancy when it is lower than 7.2℃ in winter. It is generally believed that apples can be planted in areas where the annual average temperature is 7.5 ~ 14℃.

The natural dormancy period of apples is very long. If the temperature in winter is too high, it can't reach the low temperature needed for winter dormancy, and the germination in spring is uneven.