Plant Migration. The Dynamics of Geographic Patter- ning in Seed Plant Species. 1988. 14 maps. 352 p. gr8vo. Cloth.

In plants, migration is defined as any change in the borders of aspecies and includes local advances and retreats as well as long-rangecolonization. Specialists will welcome Professor Sauer's original andfinely constructed account of plant migration, through cases that aredocumented by actual historical or fossil evidence. Two of the principalquestions addressed are how such migrations are initiated and guided bychanging seed dispersal and environmental selection, and how theprocesses of migration and evolution interact. The author includes that,contrary to accepted theory, migrations documented by direct evidencewith time depth do not usually resemble migrations that would bepostulated by deduction from present distributions. Real migrations arefar more complex, individualistic, and interesting than those based onlogical models. Without claiming to offer the last word on plantmigration, this work is a landmark assessment of what is presentlyknown, and not merely assumed, about the process.