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Lineage‐specific traits determine how plants interact with their surrounding environment. Unrelated species may evolve similar phenotypic characteristics to tolerate, persist in, and invade environments with certain characteristics, resulting in some traits becoming relatively more common in certain types of habitats. Analyses of these general patterns of geographical trait distribution have led to the proposal of general principles to explain how plants diversify in space over time. Trait–environment correlation analyses quantify to what extent unrelated lineages have similar evolutionary responses to a given type of habitat. In this synthesis, I give a short historical overview on trait–environment correlation analyses, from some key observations from classic naturalists to modern approaches using trait evolution models, large phylogenies, and massive data sets of traits and distributions. I discuss some limitations of modern approaches, including the need for more realistic models, the lack of data from tropical areas, and the necessary focus on trait scoring that goes beyond macromorphology. Overcoming these limitations will allow the field to explore new questions related to trait lability and niche evolution and to better identify generalities and exceptions in how plants diversify in space over time. [ABSTRACT FROM AUTHOR]

The monocot family Cyclanthaceae (Pandanales) comprises ca. 230 known species in 12 genera restricted to the Neotropics. The family has not been the subject of a species‐level molecular phylogenetic study to date, with multiple evolutionary and biogeographic questions about Cyclanthaceae still unanswered. In this study, we address genus‐ and species‐level relationships and the historical biogeography of Cyclanthaceae based on a broadly sampled molecular phylogeny. Two low‐copy nuclear genes (phyC, rpb2) and five plastid regions (atpB‐rbcL, psbA‐trnH, trnL‐trnF, trnQ‐rps16, matK) representing 99 species and all genera of Cyclanthaceae were sampled, spanning the taxonomic and biogeographic diversity of the family. Our results strongly support the monophyly of all Cyclanthaceae genera and confirm previously proposed hypotheses of intergeneric relationships. Infrageneric relationships are generally well supported, with some exceptions in the genus Asplundia that may require a broader sampling to clarify. The early diversification of Cyclanthaceae is estimated to date back to the Paleocene‐Eocene period in South America, where the family possibly arrived through a boreotropical route. The origin of most genera is inferred from the Paleocene of the Tumbes‐Chocó‐Magdalena region, possibly indicating an earlier origin for this biodiversity hotspot. The current distribution of Cyclanthaceae is likely to have been strongly influenced by major biogeographical events in the Neotropics, such as the uplift of the Andes and the opening of the South America dry diagonal. Further studies that include a broader sample of the large Asplundia‐Dicranopygium clade and Sphaeradenia group are required. [ABSTRACT FROM AUTHOR]

Eugenia, comprising ca. 1100 species, is the largest genus of Neotropical Myrtaceae. Eugenia sect. Umbellatae (formerly referred to as "clade 9") is the most speciose lineage of Eugenia. This study aims to better delimit E. sect. Umbellatae, to identify and understand relationships between manageable subgroups of this large clade for future discrete systematic studies and to explain biogeographical patterns in the genus. In total, 103 samples were used in this study. These include representatives of the nine clades of the "Eugenia group" with a particular focus on Eugenia clade 9, representing the morphological and geographical diversity found in the genus. Phylogenetic reconstructions were performed using maximum likelihood (ML) and Bayesian inference (BI) for the combined dataset, using the markers ITS, rpl16, psbA-trnH, rpl32-trnL, trnQ-rps16. The resultant tree was fossil calibrated and used for historical biogeographical analysis using DEC implemented in RASP. The mid Oligocene is the most likely period in which the crown node of Eugenia s.l. diversified. The earliest Eugenia appear to be associated with dry biomes and to have arisen from non-tropical southern South America, as did ancestors of the earliest American Myrteae. Eugenia subg. Pseudeugenia also most likely diversified in dry biomes, while E. subg. Hexachlamys and E. subg. Eugenia are likely to have diverged in the Atlantic Forests biome. Eugenia sect. Umbellatae is morphologically very variable,some clades can be circumscribed based on morphology while some remain morphologically undiagnosable. The study presented here provides discussion of the earliest origins of Eugenia and its response to climate-driven changes in the Neotropics as humid, forest biomes became more widespread in the Miocene. In addition, important practical conclusions are drawn regarding relationships within Eugenia. Three clades are newly classified as subgenera: E. subg. Pseudeugenia (including species of E. sect. Pseudeugenia),E. subg. Hexachlamys (including E. sect. Hexachlamys) and E. subg. Eugenia (including E. sect. Umbellatae, E. sect. Jossinia, E. sect. Phyllocalyx, E. sect. Pilothecium, E. sect. Racemosae, E. sect. Schizocalomyrtus, E. sect. Speciosae and Eugenia sect. Excelsae). Two previously unidentified clades are published as E. sect. Excelsae and recognized as E. sect. Jossinia, the latter consisting entirely of Old World species. [ABSTRACT FROM AUTHOR]