Leaf architecture of Zanthoxylum(Rutaceae)from China and its taxonomic significance

Leaf architecture of 32 species and 4 variety of Zanthoxylum s.l.(Rutaceae)in China were investigated.A comprehensive description of leaf architecture for Zanthoxylum was provided.Venation pattern was brochidodromous which represented a comparative primitive type.Tree types of teeth were detected,namely entire,toothed and crenate.The secondary veins were branched or unbranched.The most species were without glands on teeth,except in 4 species.These results did not support Englerian classification of Zanthoxylum.Based on comparison of leaf architecture,our results supported the taxonomic treatment of subgenera Fagara and Zanthoxylum as subgenus rank of Zanthoxylum and the genus Zanthoxylum as a comparative primitive group within the Rutaceae.A key based on main diagnostic morphologically and leaf architecture characters to the two subgenera of Zanthoxylum were revised.