50 years of plant speciation

Summary Levin, D. A.: 50 years of plant speciation. – Taxon 50: 69–91. 2001. – ISSN 0040‐0262. During the past fifty years our understanding of plant speciation has exploded due to the application of molecular techniques and to creative thinking and ingenious experiments. Some of the major advances regarding adaptive radiation, the lability of ecologically relevant traits, genetical and chromosomal changes associated with speciation, the tempo of speciation, recombinational speciation, and the geography of speciation are reviewed. It is apparent that the process of speciation may, but need not be, dependent on a small number of genetic and/or chromosomal changes and that speciation may occur rapidly, even without polyploidy. Speciation likely is a local phenomenon most likely involving a few local populations or a metapopulation. Polyploid taxa are dynamic entities, often by virtue of multiple origins and intragenome changes and intergenome rearrangements. The rate of evolution remains one of the most untractable issues.