Flowers and leaves of apple trees:

Leaf blade oval, ovoid to wide oval, 4.5-10cm long and 3-5.5cm wide, with sharp apex, wide wedge-shaped or round base, rounded serrations at the edge, pubescent on both sides when young, and hairless at the top when growing up; Petiole stout, about 65438 0.5-3 cm long, pubescent; Stipules herbaceous, lanceolate, apex acuminate, entire, densely pubescent, caducous.

Corymb with 3-7 flowers clustered at the top of branchlets, pedicel length 1-2.5 cm, densely tomentose; Bracts membranous, linear-lanceolate, apex acuminate, entire, tomentose; Flowers 3-4 cm in diameter; Calyx tube densely tomentose outside; Sepals triangular-lanceolate or triangular-ovate, 6-8 mm long, tapering at the top, entire, densely tomentose on both sides, sepals longer than calyx tube; Petals are obovate, long 15- 18 mm, with short claws at the base, and white and pink when the buds are not released; Stamens 20, filaments uneven in length, about half of petals; Style 5, lower part densely gray tomentose, slightly longer than stamens.

The flower bud differentiation of pear trees takes place in the first summer. After the primordium of each part of the flower is formed, the flower bud goes into dormancy and can not bloom until the next spring. Because the temperature required for the growth of flower buds of these flowers and trees is lower than that required for the growth of leaf buds, the temperature in early spring has met their growth needs, so the flower buds gradually expand and open. However, the temperature at this time can not meet the growth needs of leaf buds, so it is still lurking. When the temperature gradually increased to meet their growth needs, the leaf buds began to germinate, so the phenomenon of flowering first and then growing leaves appeared. If the temperature required for flower buds and leaf buds to grow is similar, then in spring, flowers and leaves bloom almost at the same time.