Clinal Variation and Species Boundaries in the Ficus petiolaris Complex (Moraceae)

The Ficus petiolaris complex, comprised of F. brandegei, F. jaliscana F. petiolaris and F. palmeri, is a group of Mexican endemic fig species where disagreement on their recognition still exists. Sixteen populations belonging to these taxa were analyzed to resolve their taxonomic status. Data on morphological and micromorphological characters were gathered. Multivariate and univariate statistical analyses as well as diagnostic character analyses were carried out with populations as units of analysis. In addition, correlation tests and regression analyses were performed with continuous morphological characters, geographic location, and the amount of precipitation to detect any clinal variation. Results indicate that continuous quantitative characters traditionally utilized to differentiate taxa in the Ficus petiolaris complex exhibit clinal variation. Petiole length, leaf width, and fig area decrease with latitude and longitude. There is a positive relationship between petiole length and leaf width with latitude and precipitation. Statistical analyses did not identify diagnostic characters for the previously recognized species. Characters such as branch pubescence, color of leaf veins, and pubescence and spots over figs utilized for differentiating taxa were found to vary within and among populations. Therefore, Ficus petiolaris, the first name described in this complex, is recognized as the only species that should be recognized, with a wide distribution from Sonora to Oaxaca and in Baja California.