Why do taller species tend to have larger seeds and fruit?
A tendency for larger species or growth forms to have larger fruits and seeds has been recognized many times previously (Leishman et al., 2000; Moles et al., 2004). In the most comprehensive study to date, seed size and maximum plant height were positively correlated across 2113 species from a wide range of habitats, including deserts, grasslands, shrublands and both temperate and tropical forests (r2 = 0·35; Moles et al. 2004). The strength of this global relationship was considerably greater than that found here. However, when just the tropical forest species from that study are considered the traits were correlated with similar strength to those among the species in this study (r2 = 0·09). It is unclear why larger species tend to have larger fruits and seeds (Leishman et al., 2000; Moles et al., 2004). While, logically, there must be a physical constraint whereby very small plants cannot support very large fruits or seeds, it seems unlikely that observed fruit and seed sizes are clo
