We use the pollen and seed producing cones of conifers as a study system to investigate the factors that generate morphological diversity over broad evolutionary timescales. We often approach these questions by asking how the broad functional demands that cones perform, such as the capture of pollen grains, the protection of maturing seeds, or the dispersal of mature seeds, shapes patterns of morphological change. Other projects have explored how cone evolution is further influenced by plant architecture, particularly how major differences in branch diameter and branching density among conifer clades constrain the evolution of cone size and influence the specific way in which reproductive resources are arrayed in the tree canopy.
Past and current projects have focused on these questions at different taxonomic and temporal scales, with a focus on integrating data from the fossil record with analyses of living diversity. For example, data from Paleozoic, Mesozoic, and modern conifer species suggest that seed cones have become proportionally wider over time, with an important shift occurring in the Jurassic. This change is primarily driven by an increasing amount of cone scale tissue relative to seed tissue, suggesting that more recent conifers devote more tissue to surrounding and protecting seeds than earlier representatives.
Leslie, A.B., Beaulieu, J.M., Crane, P.R., and Donoghue, M.J. 2014. Cone size is related to branching architecture in conifers. New Phytologist 203: 1119-1127.
Leslie, A.B., Beaulieu, J.M., Crane, P.R., and Donoghue, M.J. 2013. Explaining the distribution of breeding and dispersal syndromes in conifers. Proceedings of the Royal Society of London B 280: 20131812.
Leslie, A.B. 2011. Predation and protection in the macroevolutionary history of conifer cones. Proceedings of the Royal Society of London B 278: 3003-3008.
Leslie, A.B. 2011. Shifting functional roles and the evolution of conifer pollen-producing and seed-producing cones. Paleobiology 37: 587-602.