Phytologia (Dec 2006) 88(3) 299 RE-EXAMINATION OF THE TAXONOMY OF THE ONE-SEEDED, SERRATE LEAF JUN1PERUS OF SOUTHWESTERN UNITED STATES AND NORTHERN MEXICO (CUPRESSACEAE) Robert P. Adams Biology Department, Baylor University, Box 97388,Waco, TX 76798, USA email [email protected] Sanko Nguyen Pharmacy Institute, University of Oslo, Blindern, 0316, Oslo, Norway. Julie A. Morris Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA Andrea E. Schwarzbach Department of Biological Sciences, University of Texas at Brownsville Brownsville, TX 78520, USA ABSTRACT The one-seeded, serrate leaf margined junipers of Southwestern United States and northern Mexico consist of J. angosturana, J. californica, J. coahuilensis var. arizonica, J. c. var. coahuilensis, J. monosperma, J. pinchotii, J. occidentalis var. australis, J. o. var. occidentalis and J. osteosperma. Recent nrDNA and trnC-trnD sequence data were compared with RAPDs analysis and two of the taxa (J. c. var. arizonica; J. o. var. australis) were found to be in separate clades. In addition, the two taxa were as distinct as other recognized species in the group. Because of this, Junipems coahuilensis var. arizonica is recognized at the specific level as J. arizonica. Since the specific name J. australis is unavailable due to prior use, J. occidentalis var. australis, was given a new name, J. grandis, to denote the robust tree nature of the big western juniper. All the remaining taxa were quite distinct in both their sequences and RAPDs data.