Leaf heteroblasty and morphotypes of Acer monspessulanum (Djurdjura, Algeria) as revealed by traditional and geometric morphometrics

Abstract

The genus Acer which is largely distributed in the Northern hemisphere is represented in Algeria by four species of which Acer monspessulanum is the most common. These four species and their putative hybrids are coexisting in many parts of their Algerian distribution range but their leaf morphology has not been the subject of quantitative analyses despite the interest of such kind of data in taxon delineation particularly in the case of interspecific hybridization. The present work is the first step towards a quantitative analysis of leaf morphology in Acer species in Algeria. We presently relied on traditional and geometric morphometrics methods in the study of Acer monspessulanum subsp. monspessulanum leaf morphology in two sites of the Djurdjura Mountain with consideration of tree and within-shoot effects. The results showed congruence between the two methods which both highlighted the presence of a marked heteroblasty. Basal leaves are twice as large as apical ones for all measured leaf features. The petiole is longer than the blade in basal leaves and inversely in apical ones. The median leaves have intermediate values. The results revealed also the coexistence of two contrasted leaf morphotypes on distinct trees of both sites.