AbstractStatistical analysis of thirty collections of Breutelia inclinata (Hamp.&Lor.) Jaeg. from two disjunct parts of the range, Mexico/Guatemala and Andean South America, reveals that plants from the two areas differ significantly in width of the leafy stems and in leaf length. While the differences are judged insufficient to warrant taxonomic recognition, the greater overall variation in collections from Mexico/Guatemala, compared with those from continental South America, is considered noteworthy. Higher levels of interpopulational variability in essentially non-sexual plants at the northern edge of the range may support a model of evolution that emphasizes local microenvironmental factors as critical rather than Darwiniaa selection forces operating on sexually reproducing populations.