SUMMARY. Nineteen Trifolium repens L. (white clover) populations were collected in different parts of Uruguay (where conditions are marginal for the species) from swards sown 2?15 years earlier. Twenty five genotypes of each population were grown as spaced plants on a single site. Leaflet length and width, petiole length, plant height, plant diameter and internode length were recorded. In a second experiment, ten of the populations were studied in a similar way.