The flow cytometric seed screen allows for identification of reproductive modes of seed formation and inference of the ploidy of contributing gametes. However, the lack of a mathematical formalization to infer male/female genomic contributions, and the prerequisite of a binucleate female contribution to the endosperm limits its applicability.We evaluated this assumption combining a DNA-based progeny survey with a comparison of the cytology of reproductive pathways co-occurring within single individuals representing 14 Potentilleae species from six phylogenetic lineages.A numerical framework valid for sexual and pseudogamous taxa was developed, enabling quantification of female and male genomes contributing to embryo and endosperm independent of gametophyte origins, numbers of sperm involved and ploidy of parents. The inference strongly depended on accurate peak index estimation. The endosperm of Potentilleae species received a binucleate female contribution in five evolutionary lineages whereas endosperm formation remained uncertain in the Tormentillae. A modified flow cytometric seed screen protocol was developed to cope with low endosperm contents.Evolutionary conservation of a binucleate female contribution to the endosperm suggested wide applicability of flow cytometric seed screen – at least in the Potentilleae. However, alternative progeny surveys and precise embryo/endosperm ploidy estimates are required for a comprehensive understanding of the cytology of seed formation.

We synthesized the results from a flow cytometric seed screen and the literature to infer the phylogenetic origin and the geographical and taxonomic distribution of apomixis in tribe Potentilleae (Rosaceae). We distinguished between regular sexuality and apomixis, the zygotic and parthenogenetic origin of the embryo, and the pseudogamous (i.e. sexual) versus autonomous origin of the endosperm. The combined evidence provides information on reproductive modes for 11 genera and 120 species. For the first time records on reproductive mode are provided for the genus Farinopsis, 29 species (from five genera), and seven series of Potentilla. Regular sexuality was observed in Aphanes,