Available online at www.sciencedirect.com The evolution of plant development in a paleontological context C Kevin Boyce Contrary to what might be expected from the observation of and imagery from the well intentioned, but unhelpful extant plants alone, the fossil record indicates that most and misleading [11,12] telome theory. aspects of vascular plant form evolved multiple times during their Paleozoic radiation. Opportunity is increasing to unite As sophistication of the molecular understanding of information from fossil and living plants to understand the developmental mechanisms has increased, so have the evolution of developmental mechanisms and each field opportunities for rapprochement. For example, the per- can provide tests for hypotheses derived from the other. vasive role of auxin in morphogenesis [13,14–16] has The paleontological context to recent advances in allowed paleontologists to use vascular patterns preserved developmental genetics is reviewed for the evolution of a in fossils as records of auxin gradients and, thereby, functionally independent sporophyte generation, of leaves, growth dynamics [17–19]. Although the auxin investi- and of roots — all of which are integral to understanding gations [13] inspiring this paleontological research have the explosive radiation of vascular plants during the Devonian, been more classical than molecular, recent advances 400 million years ago. regarding transient maxima in auxin production and reversibility of auxin pumping ([20–22], reviewed in Address [23,24 ]) will be essential for understanding the more Department of the Geophysical Sciences, University of Chicago, 5734 S. derived vascular patterns of fossil and extant plants. More Ellis Avenue, Chicago, IL 60637, USA broadly, differences in morphological disparity between independent derivations of functionally equivalent Corresponding author: Boyce, C Kevin (
[email protected]) organs may reflect the constraints of their alternative patterning mechanisms.