Apomixis in model systems has been of growing interest for many scientists around the world. A limited number of species belonging to Brassicaceae has been described as apomictic and considered as a model system to study molecular biology of apomixis. In this study, we report the use of an ovule-clearing technique to characterize embryo sac development in Arabis gunnisoniana. The embryo sac development was detected by Taraxacum-type diplosporous dyad formation. Hence, the reproductive pathways in Arabis gunnisoniana were revealed by using flow cytometric seed screen (FCSS) analysis. Arabis gunnisoniana appears to display pseudogamous apomixis.