Cladistic biogeographic methods remain susceptible to the confounding effects of "pseudo-congruence" and "pseudo-incongruence" because they were not designed to incorporate information on the absolute timing of the diversification of lineages. Consequently, results from cladistic biogeographic studies are difficult to interpret and cannot be confidently attributed to any particular cause. We illustrate these points with concrete examples, paying special attention to recent work on the biogeography of the Northern Hemisphere, and outline ways in which topological and temporal information might be better integrated. The development of historical biogeography over the last few decades provides general insights into the nature of integration through the life of a discipline.