XVI International Botanical Congess

In spite of their prominent ecological role in Mediterranean scrub communities and potential for evolutionary studies, Rock roses (~200 species, 7-8 genera) have largely been neglected. This project was designed to infer phylogenetic relationships from chloroplast matK, trnL-F, and nuclear ITS sequences, including sampling across all genera, subgenera and sections. Counter to some hypotheses, shrublets (e.g. Helianthemum) are basal to showy-flowered, lofty shrubs (e.g. Cistus) and herbs (e.g. Tuberaria). Helianthemum, the only genus to contain New and Old World species, is not monophyletic, suggesting resurrection of Spach's Crocanthemum. Phylogenetically informative characters, mostly unused in classical cistalean taxonomy, appear to be pollen, stigma and style morphology, calyx development, corolla color, chromosome number and host-parasite associations.