Study on DNA extraction of Zelkova EXAMINATION ON THE TYPE OF ZELKOVA SPACH(ULMACEAE) A New Variety of Zelkova schneideriana ‘HenTianGao’ Physiological and Biochemical Changes in Zelkova serrata Leaves during Leaf color Transformation in Autumn Chromosome Numbers and Karyotypes of Three Zelkova Species Fingerprinting construction for superior individuals of Zelkova schneideriana based on CE-SRAP A preliminary study of molecular phylogeny and biogeography distribution pattern of Zelkova inferred from trnL-trnF and nrITS sequences