海棠类植物是蔷薇科苹果属和木瓜属的统称,种类繁多,品种丰富,各品种间观赏特性差异大。苹果属植物在全世界共有35种,亚洲、欧洲及北美洲均有分布,我国是其分布中心,约有25种,而在食用的苹果品种及观赏的木本花卉中,海棠品种不计其数。国际上通常将此属植物中的栽培品种,按其果实大小划分为苹果与海棠两大类,其中果实直径大于5cm的为苹果,小于5cm的为海棠。近100年来,在全世界 Begonia plants are Rosaceae apple genus and papaya genus collectively, a wide variety, rich variety, different varieties of ornamental differences. Apple species in the world a total of 35 species, Asia, Europe and North America are distributed in China is the distribution center, about 25 species, and in the consumption of apples varieties and ornamental woody flowers, Begonia varieties countless . Internationally, the cultivars in this genus are generally divided into two categories of apples and begonias according to the size of their fruits, of which apples whose fruit diameter is larger than 5 cm and begonias smaller than 5 cm. Nearly 100 years in the world