Seeds of Vitaceae can be easily recognized by their unique features, a pair of ventral infolds and a dorsal chalaza knot, but the inter- and intrageneric morphological variation in seed morphology has not been explored in detail. To facilitate identification of genera based on seed morphology, a study of 252 extant seeds representing all 15 genera of Vitaceae was conducted with attention to morphological characters and seed coat anatomy. Principal-component analyses were employed to assess the variation of seed morphology. Shape and position of ventral infolds and chalaza, shape of ventral-infold cavities, and testa anatomy are characters that can generically differentiate vitaceous seeds. Typically, seeds of Leea, Cissus, Cyphostemma, Tetrastigma, Rhoicissus, and Cayratia have a long or linear chalaza, whereas those of the rest of the family usually have an oval chalaza. Nevertheless, some seed forms occur in more than one genus, and some genera possess more than one seed form. The overlapping seed morph...