Identification of morphological traits defining taxa based on lineage divergences in the Tamus clade
We explored whether differences may exist between the four clades identified in the Tamus clade of Dioscorea in macro- and micromorphological characteristics (Figure 5). Only three traits (male flower pedicel, female inflorescence length and leaf coverage) were found to have a normal distribution (Supplementary Data Table S3). An assumption of homoscedasticity was corroborated using a Levene test for these variables. In the vegetative traits analysed (Supplementary Data Table S2), we found significant differences between clades in leaf area, including leaf length, leaf width, leaf perimeter and petiole, while leaf coverage and the main nerve length and leaf length ratio did not show significant differences between groups (Supplementary Data Table S3). Regarding reproductive traits (Supplementary Data Table S2), we found significant differences in male individuals for the total length of the inflorescence, the length of pedicels and the number of fascicles, but the number of flowers did not show significant differences (Supplementary Data Table S3B). The following morphological traits showed Pearson correlations >0.7 (Supplementary Data Figure S7): leaf length, leaf width, leaf area, leaf perimeter, petiole, leaf coverage, main nerve length, leaf length ratio, inflorescence length and number of flowers. We therefore selected leaf area, leaf coverage and male inflorescence length as potential diagnostic variables. Post-hoc analyses were performed (Supplementary Data Table S3), and we used these statistical differences to describe the morphological variability of each genetic group in Table 2.