Kingdonia uniflora Balfour f. et W. W. Smith is endemic to China. Pollen grains of this species were examined under light microscope and scanning electron microscope, and the structure of exine under transmission electron microscope.

     The pollen grains are tricolpate, prolate or subprolate, 27.8-35.7μ× 23.5-29.6μ. There are some granules on the colpus membranes. The exine is semitectate, striato-reticulate, and 2-layered, with distinct tectum and columllae. According to Walker's idea about pollen evolution in primitive angiosperms, the pollen of the genus does not seem to be primitive.