Systematic implications of seed coat diversity in some representatives of the genus Ipomoea (Convolvulaceae)

Seed coat morphology of 15 species of Ipomoea L. was examined comparatively using scanning and light microscopy methods in order to evaluate their diagnostic value for systematic studies. Macro- and micromorphological characters, including seed shape, colour, size, seed surface, epidermal cell shape, anticlinal boundaries, and periclinal cell wall are presented. Descriptions of seed size, shape, colour, surface, and seed coat types are summarised for the genus. Taxonomic phylogenetic implications of the seed coat micromorphology are also discussed in comparison with the available gross morphological and molecular data. Results of the seed character analyses offer useful data for evaluating the taxonomy of Ipomoea both on subgeneric and sectional levels. Monophyly of both sections Erpipomoea Choisy and Eriospermum Hallier is not supported. A key for the identification of the investigated taxa based on seed characters is provided.