Progress in understanding angiosperm history, success, and relationships: Darwin's abominably "perplexing phenomenon".

Abstract

To Charles Darwin the suddenness of the angiosperm appearance and their rapid rise to dominance in the fossil record was both a “perplexing phenomenon” to “those who believe in extremely gradual evolution” and an “abominable mystery” (1). It has been 125 years since Darwin's letter to Heer and for most of this time the investigation of the mystery has been in the domain of comparative morphology, traditional taxonomy, and the fossil record, principally of pollen and leaves. These approaches have failed to illuminate the mystery that has now grown to include major aspects of angiosperm phylogeny, evolutionary success, and origin (2). But lately, exciting new methods and data are available that have enormous potential to resolve this set of problems. New kinds of fossils have been discovered from critical times (2–4); new algorithms are available for the rapid comparative analysis of all kinds of data (5), and molecular genetics is providing data on nucleic acid sequences and homeotic genes like the MADS family (6–12). These allow invaluable insights into homology of floral organs.