Abstract: In the present work, pollen grains of 3 species of Liriope, 24 species of Ophiopogon and 2 species of Peliosanthes were examined under scanning electron microscope, Among them 4 species were also observed under transmission electron microscope. The observation (Table 3)shows that Liriope and Ophiopogon distinctly differ from Peliosanthes in the exine ornamentation and structure, They may be divided into two types: 1. Rugulate-perforate, ektexine with perforate tectum in Liriope and Ophiopogon. 2. Verrucate, Verracae unequal in size, ektexine intectate in Peliosanthes. Pollen morphology shows the close affinity between Liriope and Ophiopogon, but they are very far from Peliosanthes. The correlation between pollen and gross morphology in Liriope, Ophiopogon and Peliosanthes are stated and their evolutionaly trends are discussed in this paper. The pollen characters support the placement of Liriope and Ophiopogon in one tribe—Ophiopogoneae, and Peliosanthes in another tribe—Peliosantheae. Peliosanthes is more advancedthan Liriope and Ophiopogon.

Key words: Liriope, Ophiopogon, Peliosanthes, Pollen morphology, exine ultrastructure