Traditional vicariance analyses of the Northern Hemisphere are destined to be confusing by virtue of mixing splitting events that occurred at different times. To avoid this problem it would be wise to sort phylogenies according to lineage divergence times and then analyze subsets of trees that are relevant to the same time period/vicariance events. As a starting point in this sorting process, we recognize two major tracks around the Northern Hemisphere: an Atlantic track characterized by species in China, Europe, and southeastern North America, and a Pacific track involving China, Japan, often western North America, and eastern North America. Here we concentrate on our recent analyses of clades showing the Pacific track. All possible patterns of relationship involving North America, Japan, and China appear among the groups we have considered. North American species are most closely related to Japanese species in Hamamelis and Viburnum sect. Pseudotinus. North American species are linked with one or more Chinese species in Triosteum and Buckleya, to the exclusion of the Japanese species. In Torreya it appears that the Chinese and Japanese species form a clade to the exclusion of the North American species. These differences either imply different vicariance events in different time periods, or differential responses to the same vicariance events coupled with extinction. We explore both possibilities, bringing estimated divergence times to bear on the problem when possible.

Key words: Asia, biogeography, divergence times, North America, Northern Hemisphere, phylogeny