The aim of this research work was to describe the genetic and chemical variability of the medicinal specie "chapéu de couro" (Echinodorus grandiflorus and other species), which is found in Rio Grande do Sul State, Brazil. The plants had been collected at sixteen different sites and planted again in an experimental area at the Federal University of Pelotas (UFPel), in the town of Pelotas-RS. The plants have grown in waterlands, by keeping them underwater during the winter and adding water when the soil was dry. The plants have been fed up with lime, ash of rice waste and vermcomposite. The leaves and the seeds have been collected during spring and summer. The phenology of the different material has been observed to proceed the botanical and physiological description of ecotypes, through field parameters and in the experimental area. The chemical composition of the major chemical substances in the leaves of both native and non native plants was also analyzed. The evaluation led to conclude that: 1- the vailing specie in Rio Grande do Sul State is Echinodorus grandiflorus; 2 - the ecotypes from Cruz Alta and São Gabriel are prefered for cropping due to their early and dry matter production; 3 - the ecotypes from Arroio Grande and Jaguarão are prefered for cropping due to your rich chemical composition.
phenology; Echinodorus; chromatography; variability; cropping