New highlights on Old World giant Phragmites (Poaceae) using leaf and floral bract microscopic characters

The genus Phragmites includes taxa that are very difficult to distinguish macroscopically, and even genetically. To better discriminate these taxa, microscopic traits, such as the epidermis of floral bracts leaves, leaf anatomy, were investigated. In Old World, four distinct giant reeds species (> 3 m) delineated: two tropical species, P. karka mauritianus, Mediterranean altissimus frutescens. Previously included within australis sensu lato, rehabilitation frutescens is supported by relevant distinctive characteristics. Conversely, small (< from temperate cold regions form a group. Although this group still subdivide with three can be separated using anatomy: both Afro-European Australian-E. Asian stricto, japonicus. Using iodine green solution, we link our morphological analyses previous genetic clustering, coloration margin teeth matches presence nuclear waxy gene bands in mauritianus (100 bp), (200 while karka, subsp. japonicus have no nor band. While anatomy features seem correlated eco-climatic conditions, epidermal traits delimited other clades. For present more ancestral characters, whereas australis, japonicus, possess derived traits. Lastly, bract separate divergent evolutionary lineages basal karka.