XVI International Botanical Congess

The morphological, anatomical, seed surface ultrastructure and interrelationships in 47 species of the tribe Astereae were studied using SEM, light microscope as an aid to clarifying the taxonomy of the tribe. Comparative study revealed the three main patterns of seed structure: Aster-type is characterazed by ovate-wedge shaped achenes, thick pericarp and isodiametric epidermis cells, Erigeron-type with ovate-lanceolate achenes, thick walled epidermis cells are elongated along the axis of achenes, Solidago-type have narrow-cylindrical achenes with numerous ribs and large number of mechanical bundles. Investigated species can be divided into 3 types, according to form of achenes, thickness of pericarp, structure of epidermal cells and arrangment of mechanical elements of pericarp. Doellingeria scabra, Galatella coreacia, Callistephus chinensis,Grindelia squarrosa show the distinguished seed structure and deserved special attention.