Phylogeny and historical biogeography of Lauraceae: Evidence from the chloroplast and nuclear genomes

Phylogenetic relationships among 122 species of Lauraceae representing 44 o f the 55 currently recognized genera are inferred from sequence variation i n the chloroplast and nuclear genomes. The trnL-trnF, trnT-trnL, psbA-trnH, and rpl16 regions of cpDNA, and the 5' end of 26S rDNA resolved major line ages, while the ITS/5.8S region of rDNA resolved a large terminal clade. Th e phylogenetic estimate is used to assess morphology-based views of relatio nships and, with a temporal dimension added, to reconstruct the biogeograph ic history of the family. Results suggest Lauraceae radiated when trans-Tet hyean migration was relatively easy and basal lineages are established on e ither Gondwanan or Laurasian terrains by the Late Cretaceous. Most genera w ith Gondwanan histories place in Cryptocaryeae, but a small group of South American genera, the Chlorocardium-Mezilaurus clade, represent a separate G ondwanan lineage. Caryodaphnopsis and Neocinnamomum may be the only extant representatives of the ancient Lauraceae flora documented in Mid- to Late C retaceous Laurasian strata. Remaining genera place in a terminal Perseeae-L aureae clade that radiated in Early Eocene Laurasia. Therein, non-cupulate genera associate as the Persea group, and cupuliferous genera sort to Laure ae of most classifications or Cinnamomeae sensu Kostermans. Laureae are Lau rasian relicts in Asia. The Persea group and Cinnamomum group (of Cinnamome ae) show tropical ampi-Pacific disjunctions here credited to disruption of boreotropical ranges by Eocene-Oligocene climatic cooling. The Ocotea compl ex accommodates remaining Cinnamomeae and shows a trans-Atlantic disjunctio n possibly derived from a Madrean-Tethyan ancestral distribution. These fin dings support Laurasian ancestry for most extant Lauraceae, with their cons iderable neotropical representation primarily derived from Early Miocene ra diation of the Ocotea complex upon reaching South America.