Abstract: The plants of the family Lauraceae are main components of evergreen broadleaved forests in southern China. There are about 20 genera 420 species of the family in China. The authors of this paper made a comprehensive and systematic study on the pollen morphology of the family Lauraceae in China by means of light microscopy and scanning electron microscopy. The paper deals with 22 genera and more than 150 species and describes each genus. They can be distinguished according to the shape of pollen grains, sculpture of exine, existance of tenuity perforation. Based on the shape of pollen grains, they can be grouped into two types: spheroidal type, subspheroidal type. Because of lacking obvious aperture, it is rather difficult to distinguish their polar axis and equator. On the basis of the sculpture and structure of exine distinguished are seven pollen types: 1. Cryptocarya type, the exine smooth or scabrate, without spines: Cryptocarya, Neocinnamomum, etc. 2. Caryodaphnopsis type, the exine without spines, but with dense verrucae on the surface: only Caryodaphnopsis. 3. Litsea type, the exine with distinct spines, without mat-shaped thickening near the base of spines, usually with perforation or tenuity: Litsea, Lindera, Neolitsea, etc. 4. Laurus type, the exine with coarse triangular spines, with longitudinalstreaks on the surface of spines, and with mat-shaped thickening near the base of spines: only Laurus. 5. Persea type, the exine with distinct spines and tenuity or perforation, usually the spines very small and dense, without mat-shaped thickening at the base of spines: Persea, Machilus, Phoebe, Nothaphoebe, Alseodaphne, Sydiclis and Octea. 6. Sassafras type, the exine with or without perforation; spines smooth, with circular mat-shaped thickening at the base of spines: Sassafras, Dehaasia, Cinnamomum and umbellularia etc. 7. Cassytha type, the exine smooth or scabrate, without spines, similar to Cryptocarga type but pollen grains very small: only Cassytha. The pollen morphology of the family Lauraceae was generally thought uniform, little variable and thus difficult to be distinguished. However, our study shows that the shape of pollen grains, the sculpture and structure of exine of the family are diverse. The present paper also discusses the evolutionary trend with taxonomic problems of these genera. Viewed from the pollen morphology, the family Lauraceae has a close relationship with the family Hernandiaceae and is similar to the family Myristicaceae in some respects. Perhaps they are groups developed from the same ancestor. The existence of perforation in the family is reported for the first time.

Key words: Lauraceae, Pollen morphology, Systematic study.