“…Thirty-two taxa of Mikania have so far been examined, including 16 different species (Ruas and Ruas, 1987;Ruas, 1989;Ruas and Aguiar-Perecin, 1997), 14 populations of M. micrantha (Ruas and Ruas, 1987;Maffei, 1996;Maffei et al, 1998Maffei et al, , 1999b and two populations of M. cordifolia (Ruas and Ruas, 1987;Maffei et al, 1999a). All the karyotypes were characterized by the presence of a secondary constriction in the long arm of chromosome 1, and Ruas and Ruas (1987), in the analysis of six species, proposed that this secondary constriction should be considered a cytological marker for the genus.…”