Using transects, a description of the aquatic and wetland vegetation of the upper Rio Namay water shed was made. To reduce heterogeneity on each transect a monothetic divisive strategy, group analysis of Crawford & Wishart (1967), was performed. Resulting groups were subjected to ordination and classification. Additional information on life and growth forms of the species and profile diagrams showing the zonation were presented. Results show three definitive vegetation types: The first (Comunidad I), dominated by Panicum polygonatum, established in vernal pools, on the border of marshes, ponds and a lagoon, indicates conditions of waterlogged soils. The second type (Comunidad II) is dominated by Leersia hexandra and Heteranthera reniformis, representing the wetland vegetation. The third, a planophytic community of Spirodela intermedia and Utricularia gibba (Comunidad III), is found on eutrophic waters in an animal waste lagoon.