Geometric Morphometrics use in the examination of subgenus Quercus leaf shape variation in Algeria

The latest findings on the taxonomic review of Quercus faginea Lam. complex using ‘traditional morphometrics’, demonstrating that the species is represented in Algeria by both Q. faginea and Q. canariensis Willd. Significant variations of the leaf form were also discernible among both species. In this study, the landmark-based geometric morphometrics analysis was used to assess the shape variation of the leaves found on oak stands. 2,600 leaves per 13 stands were collected and scanned, and then using Tps range and MorphoJ software, 11 landmarks—that represent the leaf morphological features—were recorded on leaf images. Shape components and non-forms variations were obtained through a full Procrustes fit followed by creating a leaf-superimposed configuration. Principal component analysis, canonical variate analysis, and discriminate analysis were used to statistically evaluate the leaf shape variability. The results revealed no clear distinction between the two species based on leaf shape. Climate change and environmental factors also appear to have possibly caused a divergent morphological evolution; a reduced leaf size with enduring indumentum—among other Q. faginea traits—could be an efficient mean of adapting to Mediterranean xeric conditions.