XVI International Botanical Congess

The taxonomic revision of the genus Mimosa in southern Mexico and Central America was undertaken. In the region, 47 species with 28 varieties, corresponding to 22 series of sections Mimadenia, Habbasia and Mimosa, are found. A key to sections and series is given, and nomenclatural changes are emphasized. The palynological study contributes adding 5% to the 22% of the species of the genus previously studied, different types, forms and sizes of polyads, bitetrads and tetrads are found. Flowering and fruiting periods of most species (37) occur in the wet season, six species bloom and fructify in the dry season and only four species have flowers and fruits all along the year. Six geographic distribution patterns are distinguished. The main evolutionary trends of the genus are discussed.