Tree of death: The role of fossils in resolving the overall pattern of plant phylogeny

Abstract

Systematics has a long history of conficting results arising from analyses of diferent categories of biologically informative data and difering analytical methods. Until the advent of numerical methods in systematics in the 1960s, evolutionary relationships were most ofen inferred from a small subset of available characters (e.g., foral structure, fruit type, pollen characters, leaf form, cuticular anatomy), and hypotheses of relationships were not routinely tested against the results from other subsets of the data (see Nixon, 1996). In retrospect, we now realize that only partly accurate “phylogenies” became widely accepted, through either relatively universal popularity or by the force-of-will of infuential authors (e.g., Haeckel, 1876). For example, while both the Takhtajan (1969) and Cronquist (1981) systems of classifcation for fowering plants have been extremely useful in a taxonomic context, they now are recognized to be collections of systematic hypotheses that were largely untested scientifcally.