LOCAL SPECIATION IN PLANTS - THE RULE NOT THE EXCEPTION

The concept that species may arise through the gradual divergence of races has been and remains widely accepted by plant evolutionists. Evidence in its favor is circumstantial. It is unlikely that species evolve through the gradual transformation of races, because there is no simple mechanism that can produce the collective transformation of a race and because some aspects of speciation involve stochastic processes. It is much more likely that species evolve in local populations or metapopulations, mechanism of speciation notwithstanding. Dispersal and colonization from the locus of speciation bind populations of the neospecies through common descent. All populations share the unique features that distinguish the neospecies from its progenitor. There is no ecological or genetic relationship among species or patterns within species that cannot be explained by the theory of local speciation.