Publications

2008
C. C. Davis, P. K. Endress, and D. A. Baum. 2008. “The evolution of floral gigantism.” Curr Opin Plant Biol, 11, Pp. 49-57.Abstract

Flowers exhibit tremendous variation in size (>1000-fold), ranging from less than a millimeter to nearly a meter in diameter. Numerous studies have established the importance of increased floral size in species that exhibit relatively normal-sized flowers, but few studies have examined the evolution of floral size increase in species with extremely large flowers or flower-like inflorescences (collectively termed blossoms). Our review of these record-breakers indicates that blossom gigantism has evolved multiple times, and suggests that the evolutionary forces operating in these species may differ from their ordinary-sized counterparts. Surprisingly, rather than being associated with large-bodied pollinators, gigantism appears to be most common in species with small-bodied beetle or carrion-fly pollinators. Such large blossoms may be adapted to these pollinators because they help to temporarily trap animals, better facilitate thermal regulation, and allow for the mimicry of large animal carcasses. Future phylogenetic tests of these hypotheses should be conducted to determine if the transition to such pollination systems correlates with significant changes in the mode and tempo of blossom size evolution.

PDF
C. C. Davis. 2008. “Floral evolution: dramatic size change was recent and rapid in the world's largest flowers.” Curr Biol, 18, Pp. R1102-4.Abstract

Recent studies clarifying the closest relatives of the world's largest flowers, Rafflesiaceae, whose floral diameters range from approximately 11 to approximately 100 cm, indicated that they evolved from tiny-flowered ancestors in a burst of floral gigantism. New data now suggest that floral size evolution within Rafflesiaceae may be more dynamic than expected, with both recent and rapid changes in flower size.

PDF
C. G. Willis, B. Ruhfel, R. B. Primack, A. J. Miller-Rushing, and C. C. Davis. 2008. “Phylogenetic patterns of species loss in Thoreau's woods are driven by climate change.” Proc Natl Acad Sci U S A, 105, Pp. 17029-33.Abstract

Climate change has led to major changes in the phenology (the timing of seasonal activities, such as flowering) of some species but not others. The extent to which flowering-time response to temperature is shared among closely related species might have important consequences for community-wide patterns of species loss under rapid climate change. Henry David Thoreau initiated a dataset of the Concord, Massachusetts, flora that spans approximately 150 years and provides information on changes in species abundance and flowering time. When these data are analyzed in a phylogenetic context, they indicate that change in abundance is strongly correlated with flowering-time response. Species that do not respond to temperature have decreased greatly in abundance, and include among others anemones and buttercups [Ranunculaceae pro parte (p.p.)], asters and campanulas (Asterales), bluets (Rubiaceae p.p.), bladderworts (Lentibulariaceae), dogwoods (Cornaceae), lilies (Liliales), mints (Lamiaceae p.p.), orchids (Orchidaceae), roses (Rosaceae p.p.), saxifrages (Saxifragales), and violets (Malpighiales). Because flowering-time response traits are shared among closely related species, our findings suggest that climate change has affected and will likely continue to shape the phylogenetically biased pattern of species loss in Thoreau's woods.

PDF
B. Ruhfel, S. Lindsay, and C. C. Davis. 2008. “Phylogenetic placement of Rheopteris and the polyphyly of Momogramma (Pteridaceae s.l.): evidencre from rbcl sequence data.” Sys Bot, 11, Pp. 49-57. PDF
2007
C. C. Davis, M. Latvis, D. L. Nickrent, K. J. Wurdack, and D. A. Baum. 2007. “Floral gigantism in Rafflesiaceae.” Science, 315, Pp. 1812. PDF
W. R. Anderson and C. C. Davis. 2007. “Generic adjustments in neotropical Malpighiaceae.” Contributions from the University of Michigan Herbarium, 25, Pp. 137-166. PDF
D. E. Soltis, J.W. Clayton, C. C. Davis, M. A. Gitzendanner, M. Cheek, V. Savolainen, A. M. Amorim, and P. S. Soltis. 2007. “Monophyly and relationships of the enigmatic family Peridiscaceae.” Taxon, 56, Pp. 65-73. PDF
2006
Y. L. Qiu, L. Li, B. Wang, Z. Chen, V. Knoop, M. Groth-Malonek, O. Dombrovska, J. Lee, L. Kent, J. Rest, G. F. Estabrook, T. A. Hendry, D. W. Taylor, C. M. Testa, M. Ambros, B. Crandall-Stotler, R. J. Duff, M. Stech, W. Frey, D. Quandt, and C. C. Davis. 2006. “The deepest divergences in land plants inferred from phylogenomic evidence.” Proc Natl Acad Sci U S A, 103, Pp. 15511-6.Abstract

Phylogenetic relationships among the four major lineages of land plants (liverworts, mosses, hornworts, and vascular plants) remain vigorously contested; their resolution is essential to our understanding of the origin and early evolution of land plants. We analyzed three different complementary data sets: a multigene supermatrix, a genomic structural character matrix, and a chloroplast genome sequence matrix, using maximum likelihood, maximum parsimony, and compatibility methods. Analyses of all three data sets strongly supported liverworts as the sister to all other land plants, and analyses of the multigene and chloroplast genome matrices provided moderate to strong support for hornworts as the sister to vascular plants. These results highlight the important roles of liverworts and hornworts in two major events of plant evolution: the water-to-land transition and the change from a haploid gametophyte generation-dominant life cycle in bryophytes to a diploid sporophyte generation-dominant life cycle in vascular plants. This study also demonstrates the importance of using a multifaceted approach to resolve difficult nodes in the tree of life. In particular, it is shown here that densely sampled taxon trees built with multiple genes provide an indispensable test of taxon-sparse trees inferred from genome sequences.

PDF
W. R. Anderson and C. C. Davis. 2006. “Expansion of Diplopterys at the expense of Banisteriopsis (Malpighiaceae).” Harvard Papers in Botany, 11, Pp. 1-16. PDF
2005
W. R. Anderson and C. C. Davis. 2005. “The Mascagnia cordifolia group (Malpighiaceae).” Contributions from the University of Michigan Herbarium, 24, Pp. 33-44. PDF
C. C. Davis, C.O. Webb, K. J. Wurdack, C.A. Jaramillo, and M. J. Donoghue. 2005. “Explosive radiation of Malpighiales supports a mid-Cretaceous origin of modern tropical rain forests.” Am Nat, 165, Pp. E36-E65. PDF
C. C. Davis, W. R. Anderson, and K. J. Wurdack. 2005. “Gene transfer from a parasitic flowering plant to a fern.” Proc Biol Sci, 272, Pp. 2237-42.Abstract

The rattlesnake fern (Botrychium virginianum (L.) Sw.) is obligately mycotrophic and widely distributed across the northern hemisphere. Three mitochondrial gene regions place this species with other ferns in Ophioglossaceae, while two regions place it as a member of the largely parasitic angiosperm order Santalales (sandalwoods and mistletoes). These discordant phylogenetic placements suggest that part of the genome in B. virginianum was acquired by horizontal gene transfer (HGT), perhaps from root-parasitic Loranthaceae. These transgenes are restricted to B. virginianum and occur across the range of the species. Molecular and life-history traits indicate that the transfer preceded the global expansion of B. virginianum, and that the latter may have happened very rapidly. This is the first report of HGT from an angiosperm to a fern, through either direct parasitism or the mediation of interconnecting fungal symbionts.

PDF
R. Samuel, H. Kathriarachchi, P. Hoffmann, M. H. Barfuss, K. J. Wurdack, C. C. Davis, and M. W. Chase. 2005. “Molecular phylogenetics of Phyllanthaceae: evidence from plastid MATK and nuclear PHYC sequences.” Am J Bot, 92, Pp. 132-41.Abstract

Plastid matK and a fragment of the low-copy nuclear gene PHYC were sequenced for 30 genera of Phyllanthaceae to evaluate tribal and generic delimitation. Resolution and bootstrap percentages obtained with matK are higher than that of PHYC, but both regions show nearly identical phylogenetic patterns. Phylogenetic relationships inferred from the independent and combined data are congruent and differ from previous, morphology-based classifications but are highly concordant with those of the plastid gene rbcL previously published. Phyllanthaceae is monophyletic and gives rise to two well-resolved clades (T and F) that could be recognized as subfamilies. DNA sequence data for Keayodendron and Zimmermanniopsis are presented for the first time. Keayodendron is misplaced in tribe Phyllantheae and belongs to the Bridelia alliance. Zimmermanniopsis is sister to Zimmermannia. Phyllanthus and Cleistanthus are paraphyletic. Savia and Phyllanthus subgenus Kirganelia are not monophyletic.

PDF
Y.-L. Qiu, O. Dombrovska, J. Lee, L. Li, B.A. Whitlock, F. Bernasconi-Quadroni, J. S. Rest, C. C. Davis, T. Borsch, K. W. Hilu, S. S. Renner, D. E. Soltis, P. S. Soltis, M.J. Zanis, J.J. Cannone, R.R. Gutell, M. Powell, V. Savolainen, L.W. Chatrou, and M. W. Chase. 2005. “Phylogenetic analyses of basal angiosperms based on nine plastid, mitochondrial, and nuclear genes.” Int J Plant Sci, 166, Pp. 815-842. PDF
W. R. Anderson and C. C. Davis. 2005. “Transfer of Mascagnia leticiana to Malpighia (Malpighiaceae).” Contributions from the University of Michigan Herbarium, 24, Pp. 45-49. PDF
2004
C. C. Davis and M. W. Chase. 2004. “Elatinaceae are sister to Malpighiaceae; Peridiscaceae belong to Saxifragales.” Am J Bot, 91, Pp. 262-273. PDF
C. C. Davis, P. W. Fritsch, C. D. Bell, and S. Mathews. 2004. “High latitude Tertiary migrations of an exclusively tropical clade: evidence from Malpighiaceae.” Int. J Plant Sci, 165, Pp. S107-S121. PDF
C. C. Davis and K. J. Wurdack. 2004. “Host-to-parasite gene transfer in flowering plants: phylogenetic evidence from Malpighiales.” Science, 305, Pp. 676-8.Abstract

Horizontal gene transfer (HGT) between sexually unrelated species has recently been documented for higher plants, but mechanistic explanations for HGTs have remained speculative. We show that a parasitic relationship may facilitate HGT between flowering plants. The endophytic parasites Rafflesiaceae are placed in the diverse order Malpighiales. Our multigene phylogenetic analyses of Malpighiales show that mitochondrial (matR) and nuclear loci (18S ribosomal DNA and PHYC) place Rafflesiaceae in Malpighiales, perhaps near Ochnaceae/Clusiaceae. Mitochondrial nad1B-C, however, groups them within Vitaceae, near their obligate host Tetrastigma. These discordant phylogenetic hypotheses strongly suggest that part of the mitochondrial genome in Rafflesiaceae was acquired via HGT from their hosts.

PDF
2002
Laurasian migration explains Gondwanan disjunctions: evidence from Malpighiaceae
C. C. Davis, C. D. Bell, S. Mathews, and M. J. Donoghue. 2002. “Laurasian migration explains Gondwanan disjunctions: evidence from Malpighiaceae.” Proc Natl Acad Sci U S A, 99, Pp. 6833-7.Abstract

Explanations for biogeographic disjunctions involving South America and Africa typically invoke vicariance of western Gondwanan biotas or long distance dispersal. These hypotheses are problematical because many groups originated and diversified well after the last known connection between Africa and South America (approximately 105 million years ago), and it is unlikely that "sweepstakes" dispersal accounts for many of these disjunctions. Phylogenetic analyses of the angiosperm clade Malpighiaceae, combined with fossil evidence and molecular divergence-time estimates, suggest an alternative hypothesis to account for such distributions. We propose that Malpighiaceae originated in northern South America, and that members of several clades repeatedly migrated into North America and subsequently moved via North Atlantic land connections into the Old World during episodes starting in the Eocene, when climates supported tropical forests. This Laurasian migration route may explain many other extant lineages that exhibit western Gondwanan distributions.

PDF
C. C. Davis. 2002. “Madagasikaria (Malpighiaceae): a new genus from Madagascar with implications for floral evolution in Malpighiaceae.” Am J Bot, 89, Pp. 699-706.Abstract

Madagasikaria andersonii is described here as a new genus and species of Malpighiaceae from Madagascar. The phylogenetic placement of Madagasikaria was estimated by using combined data from ndhF and trnL-F chloroplast sequences and phytochrome (PHYC) and ITS nuclear sequences. It forms a strongly supported clade with the Malagasy endemic genera Rhynchophora and Microsteira. Despite nearly identical floral morphology among species in this clade (here called the madagasikarioid clade), these genera are easily distinguishable on the basis of their fruits. The schizocarpic fruits of Madagasikaria have distinctive mericarps. Each mericarp has a lateral wing, which completely encircles the nut, and a peculiar dorsal wing, which folds over on itself. The morphology of this fruit suggests that the homology of the unusual wing in Rhynchophora is lateral in nature and represents a reduced wing similar to the lateral wing in Madagasikaria. Taxa in the madagasikarioid clade all appear to be morphologically androdioecious and functionally dioecious, producing both staminate and "bisexual" (i.e., functionally carpellate) individuals. This condition appears to be exceedingly rare in flowering plants and has important implications for floral evolution within Malpighiaceae. Neotropical Malpighiaceae are pollinated by specialized oil-collecting anthophorine bees of the tribe Centridini and exhibit highly conserved floral morphology despite tremendous diversity in fruit morphology and habit. These oil-collecting bees are absent from the paleotropics, where most members of the Malpighiaceae lack both the oil glands and the typical floral orientation crucial to pollination by neotropical oil-collecting bees. The madagasikarioids represent one shift from the neotropical pollination syndrome among Old World Malpighiaceae.

PDF

Pages