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The genus Saussurea belongs to Compositae. It is composed of about 400 annual, biennial or perennial species over the world, distributed in Asia and Europe, and about 264 species are found in china. The genus have important medical value, So far, some works have been done on the medicine, cytology, molecule, physiology and morpholo gy of the Saussurea DC. by former researchers, but there are prodigious disputes remained on the systematic studies of Saussurea DC. Micromorphological characters of pollen morphology and fruit surface have important signification. We studied Saussurea DC.which were obtained from in the eastern fringe of the Qinghai-Tibetan plateau. Pollen morphology and micromorphological characters of achene surface of 26 species of Saussurea DC.were observed by scanning electron microscope and compared. So this paper can afford some basic scientific data for the discussion on the systematic relationships of Saussurea DC.and further exploitation and utilization of the Saussurea DC. The results are listed as follows:1 The pollen morphology in this genus is highly unanimous.The pollen grains are sub-spherical or spherical with 3-colporate, 3-lobate circular in polar view. The surface of exine is spinulate. Some interspecific differences exist in exine ornamentation, colpus width, spinulate size, distribution density and pollen size.2 By the ornamentation, the pollen grains of the genus can be divided into 4 types, socket, granules, reticulate -granules and reticulate.3 According to micromorphological characters, the achene surface feature can be divided into four types, striate ornamentation, septate striate ornamentation, reticulate ornamentation and negative reticulate ornamentation.4 The achene ultrastructure features were constant in infraspecies. At the same time, interspecific features were similar in same section and distinctive in different ones. Therefore, it seemed to be useful to use ultrastructures in S.saussurea taxonomy at subgenus and section level.5 Based on cluster analysis, this genus could be divided into six groups belonging to S.Subgen. Eriocoryne (DC.) Hook. f., S.Subgen. Amphilaena (Stschegl.) Lipsch, S.Subgen.Theodorea (Cass.) Lipsch and S.Subgen. Saussurea respectively.
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