Comparisons of differences between morphological means of individual plant parts indicate that the greatest source of variation in two populations ofBalsamorhiza sagittatais the individual plants within populations; within-population diversity is greater than among-population diversity. Variable covariance and correlations differ between individual plants and there are subgroups of interrelated variables that can be tied to developmental phenomena. The relationship between developmental phenomena and these groups of variables suggests a relationship between organizational, as reflected in variable interrelationships, and ontogenetic variation. These results are not adequately explained by neoDarwinian theory but are explained more comprehensively by a theory of evolution that views biological change over time as an intrinsically driven self-organization, accompanied by an increase in complexity (a manifestation of the "Second Law of Thermodynamics" as it applies to open systems).