Abstract: Due to the unique floral and pollen morphology of the genus Craigia its systematic position, whether in the family Sterculiaceae or in the family Tiliaceae, has often been debated. In order to add more evidence for solving this problem, a comparative study on pollen morphology of the genus and 15 species of 3 tiliaceous genera, viz.: Tilia Linn., Hainania Merr. and Excentrodendron Chang. et Miau. was carried out under the light and scanning electron microscope. The result shows that the polarity, the structure and position of the aperture of Craigia pollen differ from those in Tiliaceae but are similar to those in Sterculiaceae. From palynology, it is more appropriate to place the genus under discussion in Sterculiaceae than in Tiliaceae.

Key words: Craigia, Sterculiaceae, Tiliaceae, Pollen morphology, Systematic position.