The morphological variation of seedlings from a single population of Pseudotsuga menziesii was examined and related to their maternal parentage (41 families) and speed of germination (selection) during the course of a common garden experiment. The largest source of variation among seedlings was attributed to within-family variation. Furthermore, within-family variable intercorrelations differed from family to family, suggesting that intrinsic causal factors are important to the generation and organization of variation. Pooled within-family variation was explored and shown to be related to the between-family variation. These results suggest that developmental and historical factors cannot be ignored in the interpretation and exploitation of sources of variation. Such considerations identify limitations to Neo-Darwinian explanations and suggest reappraisal of progeny trials with respect to these issues. The results also pose limitations to our interpretations of genetic similarity on the basis of multivariate morphological data.