Systematics and Evolution of Palms
Uncovering the evolutionary history of the quintessential tropical rainforest family.
Molecular phylogenetic collaborations at Kew have demonstrated that the extraordinary bipinnate-leaved palm genus Caryota (pictured here) and its relatives Wallichia and Arenga are embedded within the fan-leaved palm subfamily C
The phylogenetic relationships among palms have been a focus of research at Kew for almost two decades. The primary objectives of this research campaign are 1) to generate phylogenetic hypotheses for the family for systematic purposes and 2) to use phylogenies to address fundamental questions about palm diversification and its broader implications for evolution in the tropics. This research involves many collaborators, students and postdocs. To date, we have published over 30 papers in this area, more than 20 since 2006. These results underpin the revised classification of the palms that forms the core of the new edition of the family monograph Genera Palmarum (Dransfield et al. 2008).
Kew’s palm phylogenetic research is primarily focused at the higher level, prioritising family- and subfamily-wide studies. Recent achievements include the publication of a complete genus-level phylogeny of palms, the first of its kind, using an innovative supertree and supermatrix approach, as well as a more detailed phylogeny of the largest subfamily Arecoideae (Baker et al. 2009, 2011). Subsequent studies have built on these results, such as a recent investigation of apocarpy in palm flowers (Rudall et al. 2011) that demonstrated unequivocally that free carpels arose several times in palms and do not represent the primitive state in palms, in contrast to traditional thinking. In another study, the complete genus-level phylogeny was dated using molecular clocks and used to explore the origin and evolution of rainforests (Couvreur et al. 2011). Because palms appear to show strong rainforest biome conservatism, it was inferred that rainforests may have existed when modern palm lineages began to diversify around 100 million years, considerably earlier than the earliest fossil record for rainforests. Increasingly, we are turning to dating methods to gain a deeper understanding of the temporal framework of palm evolution and for making increasingly sophisticated biogeographic inferences.
Key papers published since 2006.
1. Asmussen, C.B., Dransfield*, J., Deickmann, V., Barfod, A.S., Pintaud, J.C. & Baker*, W.J. (2006). A new subfamily classification of the palm family (Arecaceae): evidence from plastid DNA phylogeny. Botanical Journal of the Linnean Society 151 (1): 15-38.
2. Bacon, C.D. & Baker*, W.J. (2011). Saribus resurrected. Palms. In press.
3. Baker*, W.J., Savolainen, V., Asmussen-Lange, C.B., Chase*, M.W., Dransfield*, J., Forest*, F., Harley*, M., Uhl, N.W. & Wilkinson, M. (2009). Complete generic-level phylogenetic analysis of palms (Arecaceae) with comparisons of supertree and supermatrix approaches. Systematic Biology 58: 240-256.
4. Baker*, W. J., Norup, M.V., Clarkson, J.J., Couvreur, T.L.P., Dowe, J.L., Lewis, C.E., Pintaud, J.C., Savolainen, V., Wilmot, T. & Chase*, M.W. (2011). Phylogenetic relationships among arecoid palms (Arecaceae: Arecoideae). Annals of Botany. doi:10.1093/aob/mcr020.
5. Baker*, W.J. & Couvreur, T.L.P. In press. Biogeography and distribution patterns of Southeast Asian palms. In “Biotic evolution and environmental change in Southeast Asia”, Gower, D.J., Johnson, K.G., Richardson, J.E., Rosen, B.R. Rüber, L. & Williams, S.T. (Eds.) Cambridge University Press.
6. Bjorholm, S., Svenning, J.C., Baker*, W.J., Skov, F. & Balslev, H. (2006). Historical legacies in the geographical diversity patterns of New World palm (Arecaceae) subfamilies. Botanical Journal of the Linnean Society 151 (1): 113-125.
7. Blach-Overgaard, A., Svenning, J.C., Dransfield*, J., Greve, M. & Balslev, H. (2010). Determinants of palm species distributions across Africa: the relative roles of climate, non-climatic environmental factors, and spatial constraints. Ecography 33: 380-391.
8. Couvreur, T.L.P., Forest, F. & Baker, W.J. (2011). Origin and global diversification patterns of tropical rain forests: inferences from a complete genus-level phylogeny of palms. BMC Biology 9: 44.
9. Cuenca, A., Dransfield*, J. & Asmussen-Lange, C.B. (2009). Phylogeny and evolution of morphological characters in tribe Chamaedoreeae (Arecaceae). Taxon 58: 1092-1108.
10. Dransfield*, J., Uhl, N.W., Asmussen-Lange, C.B., Baker*, W.J., Harley*, M.M. & Lewis, C.E. (2008). Genera Palmarum - evolution and classification of the palms. Royal Botanic Gardens, Kew.
11. Kissling, W.D., Baker, W.J., Balslev, H., Barfod, A.S., Borchsenius, F., Dransfield, J., Govaerts, R. & Svenning, J.-C. In Press. Quaternary and pre-Quaternary historical legacies in the global distribution of a major tropical plant lineage. Global Ecology and Biogeography.
12. Loo*, A.H.B., Dransfield*, J., Chase*, M.W. & Baker*, W.J. (2006). Low-copy nuclear DNA, phylogeny and the evolution of dichogamy in the betel nut palms and their relatives (Arecinae; Arecaceae). Molecular Phylogenetics and Evolution 39 (3): 598-618.
13. McInnes, L., Baker, W.J., Barraclough, T.G., Dasmahapatra, K.K. Goswami, A. Harmon, L.J., Morlon, H., Purvis, A., Rosindell, J. Thomas, G.H. Turvey, S.T. & Phillimore, A.B. (2011). Integrating ecology into macroevolutionary research. Biology Letters. doi: 10.1098/rsbl.2011.0358
14. Nadot, S., Sannier, J., Barfod, A.S. and Baker, W.J. In press. Evolution of the palm androecium as revealed by character mapping on a supertree. In "Flowers on the tree of life", Wanntorp, L. & L. Ronse de Craene, L. (Eds.) Cambridge University Press.
15. Norup, M.V., Dransfield*, J., Chase*, M.W., Barfod, A.S., Fernando, E.S. & Baker*, W.J. (2006). Homoplasious character combinations and generic delimitation: a case study from the Indo-Pacific arecoid palms (Arecaceae: Areceae). American Journal of Botany 93 (7): 1065-1080.
16. Rudall, P.J., Ryder, R.A. & Baker, W.J. (2011). Comparative gynoecium structure and multiple origins of apocarpy in coryphoid palms (Arecaceae). International Journal of Plant Sciences. 172: 674–690.
17. Sannier, J., Asmussen-Lange, C.B., Harley*, M. & Nadot, S. (2007). Evolution of microsporogenesis in palms (Arecaceae). International Journal of Plant Sciences 168 (6): 877-888.
18. Sannier, J., Baker*, W.J., Anstett, M.-C. & Nadot, S. (2009). A comparative analysis of pollinator type and pollen ornamentation in the Araceae and the Arecaceae, two unrelated families of the monocots. BMC Research Notes 2 145: 1-11.
19. Thomas, M.M., Garwood, N.C., Baker*, W.J., Henderson, S.A., Russell, S.J., Hodel, D.R. & Bateman, R.M. (2006). Molecular phylogeny of the palm genus Chamaedorea, based on the low-copy nuclear genes PRK and RPB2. Molecular Phylogenetics and Evolution 38: 398-415.
20. Trénel, P., Gustafsson, M.H.G., Baker*, W.J., Asmussen-Lange, C.B., Dransfield*, J. & Borchsenius, F. (2007). Mid-Tertiary dispersal, not Gondwanan vicariance explains distribution pattern in the wax palm subfamily (Ceroxyloideae: Arecaceae). Molecular Phylogenetics and Evolution 45: 272-288.
21. Zona, S, Francisco-Ortega, J., Jestrow, B., Baker, W.J. & Lewis, C.E. Online Early. Molecular Phylogenetics of the Palm Subtribe Ptychospermatinae (Arecaceae). American Journal of Botany.
Project partners and collaborators
Asmussen-Lange, Conny (University of Copenhagen)
Balslev, Henrik (University of Aarhus)
Barfod, Anders (University of Aarhus)
Blach-Overgaard, Anne (University of Aarhus)
Borchsenius, Finn (University of Aarhus)
Eiserhardt, Wolf (University of Aarhus)
Kissling, Daniel (University of Aarhus)
Svenning, Jens-Christian (University of Aarhus)
Couvreur, Thomas (Institut de Recherche pour le Développement, Montpellier)
Nadot, Sophie (Université Paris-Sud)
Wilkinson, Mark (Natural History Museum, London)
Zona, Scott (Florida International University)
Bacon, Christine (University of Colorado/Smithsonian Institute)
University of Aarhus
University of Colorado