1. College of Forestry and Horticulture, Hubei Minzu University, Enshi 445002, China
2. Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
3. Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China
4. Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China
5. East African Herbarium, National Museums of Kenya, Nairobi P.O. Box 45166 00100, Kenya