摘要：X PACHEBERGIA (BACKEBERGIA — PACHYCEREUS), A NEW NOTHOGENUS FROM WESTERN MEXICO, IS PROPOSED. STEM AND SEED MORPHOLOGY OF THIS POORLY KNOWN TAXON FROM DRY TO VERY DRY DECIDUOUS TROPICAL FOREST IN THE BALSAS RIVER BASIN, GUERRERO, ARE DESCRIBED AND ILLUSTRATED. ITS DIAGNOSTIC MORPHOLOGICAL CHARACTERS AND RELATIONSHIPS WITH PACHYCEREUS PECTENABORIGINUM AND BACKEBERGIA MILITARIS, ITS PUTATIVE PARENTAL TAXA, ARE DISCUSSED.
关键词：Backebergia;Balsas River Basin;hybrid;new nothogenus;Pachycereus;Backebergia;cuenca del Balsas;híbrido;notogénero nuevo;Pachycereus
