Seed size distributions of fleshy-fruited species are more right-skewed compared to that of dry-fruited species

•We compiled the first dataset on skewness of seed size distribution.•The dataset encompasses 103 species, belonging to 72 genus and 33 families.•Skewness varied among species, ranging from -1.4 to 4.84.•Fleshy-fruited species was more right skewness in seed size than dry-fruited species.