Abstract: Seventy-two chemical components of essential oils from the leaves of 110 species and cultivars of Citrus were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Among the plants analyzed, there are 3 species in papeda, 12 species and cultivars in Osmocitrus, 18 cultivars in C. aurantium L., 15 cultivars in C. sinensis Osbeck, 16 species and cultivars in Citrophorum, 16 species and cuhivars in Cephalocitrus, 30 species and cultivars in Acrumen. As resources of essential oils, some valuable plants were found such as Citrus hystrix D. C., C. junos (Sieb.) Tan. cv. Xiecheng, C. junos (Sieb.) Tan. cv. Luohancheng and C. tankan Hayata. Our study has provided systematic data of the chemical components of the essential oils for the taxonomic work of Citrus plants.

Key words: Citrus, Essential oil, Taxonomy, Gas chromatography (GC), Gas chromatographymass spectrometry (GC-MS)