Abstract: The present study on pollen grains of the genus Viburnum Linn. Shows that: 1. The pollen characteristics are of no significance in division of sections, but each species has its own pollen characteristics. 2. The exine can be divided into three types: I. Exine semitectate, reticulate, muri psilate; II. Exine semitectate, reticulate, muri verrucate; III. Exine intectate, retipilate or pilate, the heads of pila verrucate. The evolutionary trend of the exine is III→II→I. 3. Four types of colpus margin are recognized: I. intectate; II. The colpus margin semitectate, reticulate; III. The colpus margin tectate; IV. Syncolpate at one pole, the margin tectate (only in V. farreri). 4. The ora can be divided into five types according to its membrane shape under SEM: I. The membrane of ora indistinct; II. The membrane of ora semispherical, discontinuous with colpus margin; III. The membrane of ora semispherical, continuous with colpus margin; IV. The membrane of ora semi-ellipsoidat, lolongate; V. The membrane of ora semi-ellipsoidal, lalongate, across the colpus like a bridge. 5. According to both pollen characters and inflorescence, the authors suggest that Sect. Pseudotinus be divided into two subsections, one including V. sympodiale, V. furcatum and V. latanoides, which have large sterile marginal flowers with the exine belonging to the Type I, and the other including only V. nervosum, which has no large sterr-ile marginal flowers with the exine belonging to the Type III.

Key words: Viburnum Linn., Pollen morphology, Classification