Seed dispersal is the movement of seeds away from the parent plant and is one of the most important factors influencing plant reproduction. Within a single species, plants generally evolve a single seed dispersal tactic. However, different physical and biotic environments may select for different tactics. Beach naupaka Scaevola taccada is a coastal shrub and distributed widely throughout the tropics. We have recently confirmed that different plants within S. taccada produce different seed types. The first seed type (PC type) has pulp (epicarp) and cork (endocarp) whilst the second (P type) has only pulp. The PC type seeds are buoyant and are also eaten by birds whereas P type seeds do not float and are only eaten by birds. Whilst individual plants grow only one fruit type, plants producing different seed types occur sympatrically with one another. In this study, we examined the distribution of seed producing types in relation to different landscapes and soil types from 101 sites on 20 Japanese islands. We found that there was no geographical pattern of distribution, but that PC seeds were more common in sand dunes, volcanic rocks, and mélange whereas C seeds were more common in limestone areas and on cliffs.