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.