Caldasia 23(1): 21-41 HISTORICAL BIOGEOGRAPHY OF THE ASTERACEAE FROM TANDILIA AND VENTANIA MOUNTAIN RANGES (BUENOS AIRES, ARGENTINA) A nuestra amiga Pilar JORGE CRISCI- V. Departamento Científico de Plantas Vasculares, Museo de La Plata, Paseo del Bosque s.n., 1900. La Plata, Argentina.
[email protected] SUSANA FREIRE-E. Departamento Científico de Plantas Vasculares, Museo de La Plata, Paseo del Bosque s.n., 1900. La Plata, Argentina. GISELA SANCHO Departamento Científico de Plantas Vasculares, Museo de La Plata, Paseo del Bosque s.n., 1900. La Plata, Argentina. LILlANA KATlNAS Departamento Científico de Plantas Vasculares, Museo de La Plata, Paseo del Bosque s.n., 1900. La Plata, Argentina. ABSTRACT Tandilia and Ventania are the only systems ofmountain ranges situated in a grassy steppe or "pampas" in the political province ofBuenos Aires in Argentina. Tandilia and Ventania have a high taxa diversity and endemicity. A historical biogeographic analysis was carried out on the basis of distributional patterns of species and infraspecific taxa of Asteraceae inhabiting Tandilia and Ventania in orderto establish the relationships ofthese mountain ranges with other areas. Two methods were applied for the analysis: panbiogeography using the compatibility track method and parsimony analysis of endemicity (PAE). Thirteen areas were delimited for the study: Southern North America and Central América, Southern Brazil, Uruguay, Pampa, Tandilia, Ventania, Chaco, Sierras Pampeanas, Sierras Subandinas, Mahuidas, Patagonia, Cen- tral Chile, and Northern Andes. The units of the study were 112 taxa inhabiting Tandilia and Ventania (endernic, naturalized, and adventicious species were not included). Both methods connect southern Brazil, Uruguay, Pampa, Tandilia, Ventania, and Sierras Pampeanas, showing that the Asteraceae biota ofTandilia and Ventania have closer relationships with the biota ofthese are as rather than with that ofSierras Subandinas, North Andean, Chaco, Patagonia, Mahuidas, and Central Chile.