Figure 3 . a) Percentage of haploidy/diploidy versus absolute latitude; b) Pruned regression tree results based on percentage of haploidy/diploidy, the total deviance explained is variance remaining in the sum of the leaves as a proportion of the variance in the entire data set. Cut off values for the most important environmental variable are given at each split, average annual temperature (TYR), potential evapotranspiration (ET0) and number of endemic species (End). The numbers at each leaf are the average percentage of haploidy/diploidy of the grid square in that group, c) The partial dependency plots showing the shape of the relationship between percentage of haploidy/diploidy and its best predictor variables; average annual temperature (TYR), potential evapotranspiration (ET0), total species richness (Stot) and maximum temperature of the warmest month (TMX).