Whereas the Salicaceae as a whole and its first two branches were well supported, all these studies were limited in taxon sampling. This topology was confirmed by subsequent studies using 82 plastid genes (Xi & al., 2012) and 17 genes from all three genomic compartments (Soltis & al., 2011). as sister to all remaining Salicaceae (Chase & al., 2002), followed by Scyphostegia Stapf. Based on rbcL sequences, the authors inferred Casearia sylvestris Sw. Phylogenetic studies by Chase & al. ( 2002) revealed the Flacourtiaceae to consist of different clades located in distant positions within Malpighiales, which were then recognized as part of Achariaceae Harms and Salicaceae Mirb. Formerly, the genus formed part of the widely polyphyletic family Flacourtiaceae Rich. 90 are found in the Neotropics (Gentry, 1996). (Salicaceae) is pantropical with approximately 200 species (Sleumer, 1980), among which ca. The Old World clade of Casearia provides another example for a late Laurasian migration starting in the Neotropics. The other clade, with Cuban endemics ( C. ternstroemioides) but also Mesoamerican and South American taxa, is not sufficiently resolved internally, to allow biogeographic conclusions. Our trees depict C. corymbosa, which exhibits significant infraspecific phylogenetic structure for the sampled Mexican and Colombian individuals, as the sister to the Caribbean clade. The Caribbean that comprises nearly all Caribbean endemics started to diversify around 9.5 Ma. From there, multiple migrations occurred to Mesoamerica and the Caribbean islands. Our reconstruction of ancestral areas using BioGeoBears indicate that South America is the ancestral area of Casearia. In order to establish a monophyletic genus concept for Casearia, we propose to also merge Euceraea and Neoptychocarpus. Pellucid dots appear to have evolved earlier than the divergence of the Casearia clade in Samydeae, and were lost in Ryania and Tetrathylacium, and thus are no synapomorphy for Casearia. We found morphological characters, such as branched inflorescences (fasciculate, glomerulous, cymose) or uniseriate stamen series, that work well to circumscribe the genus, whereas dioecy, which was used to diagnose Neoptychocarpus, or higher stamen numbers (>12), found in Laetia and Zuelania, are homoplastic in Salicaceae, the latter character derived within Casearia from ancestors with 7–12 stamens.

We used BayesTraits to reconstruct the evolution of seven characters commonly used to define Casearia and allied genera. The stem of the Old World clade diverged from Neotropical ancestors around 27 Ma, in the Oligocene. Our divergence date estimates using the plastid dataset and fossil calibration points in Salicaceae indicate that the Casearia crown group started to diversify during the late Eocene, approximately 39 Ma. Another clade, which includes all Palaeotropical species, is nested among Neotropical lineages. Casearia is constituted by several major clades, mostly being entirely Neotropical, one of which exclusively comprises species endemic to the Caribbean islands. Our phylogenetic analyses based on four combined rapidly evolving plastid regions ( petD, rpl16, rps4-trnT-L-F, trnK-matK-psbA) as well as nuclear ITS revealed Casearia as monophyletic with high support, including not only the former members of Laetia, Samyda and Zuelania but also Euceraea and Neoptychocarpus. We further put a focus on the Neotropical taxa since Casearia and allies are speciose both on the Caribbean islands and adjacent mainlands, thus providing an interesting group to address the origin of the Caribbean and Cuban flora. We tested the monophyly of Casearia and examined the relationships of its species to other taxa of the tribe Samydeae, including Laetia, Samyda and Zuelania, which recently have been sunk into Casearia, as well as Euceraea, Lunania, Neoptychocarpus, Ryania and Tetrathylacium. Despite the availability of phylogenetic studies that suggest that Casearia sensu Sleumer is not monophyletic, a strong phylogenetic framework was still lacking for this genus. Casearia (Salicaceae) is a pantropical genus of circa 200 species, around half of which dwell in the Neotropics.