Implication of morphological and molecular studies on taxonomic treatment of Acer L. spp. and some selected taxa of Sapindaceae Juss. s.l

Abstract

The concept of Sapindaceae has a great conflict among different classification systems, due to the close relationship with Aceraceae. Many recent studies nested the Acer within Sapindaceae based on morphological and molecular criteria. This study aims to assess the potentiality of macro-, micro-morphological as well as molecular criteria (ScoT analysis) for clarifying the taxonomic position of the two Acer species in relation to Sapindaceae s.s. Acer oblongum & A. negundo in addition to 12 taxa of Sapindaceae were collected to investigate the morphological and anatomical characteristics of stem, petiole & lamina as well as the genetic diversity based on SCoT polymorphism. These data were numerically analyzed using UPGMA clustering methods. The habit, leaf composition, laticifers, and vascular supply specially of petiole and mesophyll types were considered diagnostic at generic and specific levels and support the alliance between the two Acer species and the remaining taxa of Sapindaceae. The resulting dendrogram from the combined anatomical and molecular data showed that; the two Acer species are closely related to the remaining studied taxa. This result encourages the placement of Acer in a distinct subfamily within Sapindaceae.