Based on the studies on the North American ornamental crabapple, the paper divided them into 3 groups: Double Group, Single-red Flower Group and Single-white Flower Group.

• 2.；在对山东北美观赏海棠品种分类研究中；依据花型和花色将其分为三大品种群:重瓣品种群、红花单瓣品种群、白花单瓣品种群。