· Plant functional traits often show strong latitudinal trends. To explain these trends, studies have often focused on environmental variables, correlations with other traits that themselves show latitudinal trends, and phylogenetic conservatism. However, few studies have systematically disentangled the relative contributions of these factors.· Using partial coefficients of determination, R2, to analyze a dataset consisting of 9,370 plant species from East Asia, we investigated factors affecting fruit type (fleshy vs. dry fruits): environmental constrains (summarized by climate region), plant growth form, and phylogenetic conservatism. · Growth form and climate region are often cited in the literature as important explanations for the higher proportion of fleshy fruited species in the tropics. Nonetheless, in our analyses they explained only 1.7% and 0.3%, respectively, of the variance in fruit type. In contrast, phylogenetic conservatism explained 79.5%. Furthermore, phylogenetic conservatism was evenly distributed along the whole phylogeny, implying that fruit type reflects both ancient and recent phylogenetic relationships.· Our findings illustrate the value in parsing out the contributions of explanatory variables and phylogeny to the variance in species' traits. They also suggest that methods using the full phylogeny to calculate partial R2 give more power than traditional methods to explore the phylogenetic patterns of functional traits.
