Abstract: Ultrastructure of pollen wall of 18species of Decaisnea, Sinofranche-tia, Holboellia Stauntonia (Lardizabalaceae), and Sargentodoxa (Sargentod-oxaceae) have been investigated by transmission electron microscopy(TEM).
The most species examined have well developed tectum and columellae; the foot layer is generally thinner and consistent; endexine is very thin in mesocolpus but very well developed in colpus. The characteristic prominents and indentations on the surface of tectum, and the grain or column like columellae are of great taxonomic significance. In Stauntonia, the varied tectum morphology reflects the advanced taxonomical position of the genus in Lardizabalaceae. The species from Sargentodoxaceae has very lardizaba-lic pollen wall structure, thus, shows closer relationship with its sister fa-mily-Larbizabalaceae.