XVI International Botanical Congess

The genera Moscharia (two species) and Polyachyrus (seven species) form a monophyletic group within Mutisieae defined by the leaves partite, with auricles, capitula with involucre 1-seriate, 1-3-flowered and aggregated in pseudocepahlia, and corollas violet. A cladistic analysis of the species of both genera was carried out using 20 morphological characters. Polarity of the characters was based on the outgroup comparison method. One cladogram was produced, with 32 steps and a consistency index of 0.75. The cladogram defines six monophyletic groups: (1) all taxa except Moscharia solbrigii and M. pinnatifida, (2) Polyachyrus annus, P. carduoides, P. cinereus, P. fuscus, P. gayi, P. sphaerocephalus, (3) P. carduoides, P. cinereus, P. fuscus, P. gayi, (4) P. cinereus, P. fuscus, P. gayi, (5) Moscharia solbrigii, M. pinnatifida. The probable ancestral geographic area for the group was determined using Bremer's method. The North Central Chile area (30-34 degrees south latitude) has the highest probability of having been part of the ancestral area of Moscharia and Polyachyrus. The study suggests recent tectonic and climatic effect on the evolution of leaf morphology and capitula in both genera.