Especie nueva de Pachyphytum (Crassulaceae) del oriente de Michoacán, México

Abstract

PACHYPHYTUM RZEDOWSKII (CRASSULACEAE) IS PROPOSED AS A NEW SPECIES AND DESCRIBED. BASED ON ITS SEMITERETE LEAVES, YOUNG INFLORESCENCE WITH SUBIMBRICATELY ARRANGED FLORAL BRACTS, AND THE RATIO OF COROLLA/CALYX SIZE (COROLLA EQUAL TO OR SLIGHTLY SMALLER THAN THE CALYX), THIS SPECIES CAN BE PLACED IN PACHYPHYTUM SECT. PACHYPHYTUM. OF THE TAXA WITHIN THIS SECTION, IT MOST CLOSELY RESEMBLES P. MACHUCAE I. GARCIA, GLASS ET CHAZARO, FROM WHICH IT DIFFERS BY THE FORM AND SIZE OF THE LEAVES, THE LENGTH OF THE PEDICELS, AND THE COLOR OF PETALS. THESE SPECIES ARE THE ONLY TWO MEMBERS OF PACHYPHYTUM KNOWN FROM THE STATE OF MICHOACAN, AND THEIR POPULATIONS ARE SEPARATED BY APPROXIMATELY 200 AIRLINE KM. ALTHOUGH P. MACHUCAE OCCURS IN THE NORTHWESTERN PORTION OF THE STATE, P. RZEDOWSKII IS FOUND IN THE EASTCENTRAL PORTION, SOUTH OF THE TRANS-MEXICAN VOLCANIC BELT, IN THE BALSAS DEPRESSION.