Myrteae (c. 2500 species; 51 genera) is the largest tribe of Myrtaceae and an ecologically important groups of angiosperms in the Neotropics. Systematic relationships in Myrteae are complex, hindering conservation initiatives and jeopardizing evolutionary modelling. A well-supported and robust phylogenetic hypothesis was here targeted towards a comprehensive understanding of the relationships within the tribe. The resultant topology was used as a base for key evolutionary analyses such as age estimation, historical biogeography and diversification rate patterns. One nuclear (ITS) and seven chloroplast (psbA-trnH, matK, ndhF, trnl-trnF, trnQ-rps16, rpl16 and rpl32-trnL) DNA regions for 115 taxa representing 46 out of the 51 genera in the tribe were accessed and analysed using maximum likelihood and Bayesian inference tools for phylogenetic reconstruction. Dates of diversification events were estimated and contrasted using two distinct fossil sets (macro and pollen) in BEAST. The subsequent dated phylogenies were compared and analysed for biogeographical patterns using BioGeoBEARS and diversification rates using BAMM. Myrteae phylogeny presents strong statistical support for three major clades within the tribe: Australasian group, Myrtus group and Main Neotropical Lineage. Dating results from calibration using macrofossil are an average of 20 million years older and show an early Paleocene origin of Myrteae, against a mid-Eocene one from the pollen fossil calibration. Biogeographic analysis shows the origin of Myrteae in Zealandia in both calibration approaches, followed by a widespread distribution throughout the still-linked Gondwana continents and diversification of Neotropical endemic lineages by later vicariance. Best configuration shift indicates three points of acceleration in diversification rates, all of them occurring in the Main Neotropical Lineage. Based on the reconstructed topology, several new taxonomic placements were recovered, including: the relative position of Myrtus communis, the placement of the Blepharocalyx group, the absence of generic endemism in the Caribbean, and the paraphyletism of the former Pimenta group. Distinct calibration approaches affect biogeography interpretation, increasing the number of necessary long distance dispersal events in the topology with older nodes. It is hypothesised that biological intrinsic factors such as modifications of embryo type and polyploidy might have played a role in accelerating shifts of diversification rates in Neotropical lineages. Future perspectives include formal subtribal classification, standardization of fossil calibration approaches and better links between diversification shifts and trait evolution.

Ethnopharmacological relevance-Plant mixtures are understudied in ethnobotanical researchAim of the study-To investigate the importance of plant mixtures (remedies consisting of at least two plants) in Dominican traditional medicine.Materials and Methods-A Spanish language questionnaire was administered to 174 Dominicans living in New York City (NYC) and 145 Dominicans living in the Dominican Republic (DR), including lay persons (who self-medicate with plants) and specialists (traditional healers). Plants were identified through specimens purchased in NYC botánica shops and Latino grocery shops, and from voucher collections.Results-The percentage of mixtures as compared to single plants in plant use reports varied between 32 to 41%, depending on the geographic location (NYC or DR) and participant status (lay person or specialist). Respiratory conditions, reproductive health and genitourinary conditions were the main categories for which Dominicans use plant mixtures. Lay persons reported significantly more mixtures prepared as teas, mainly used in NYC to treat respiratory conditions. Specialists mentioned significantly more botellas (bottled herbal mixtures), used most frequently in the DR to treat reproductive health and genitourinary conditions. Cluster analysis demonstrated that different plant species are used to treat respiratory conditions as compared to reproductive health and genitourinary conditions. Interview participants believed that combining plants in mixtures increases their potency and versatility as medicines.Conclusions-The present study demonstrates the importance and complexity of plant mixtures in Dominican traditional medicine and the variation in its practices influenced by migration from the DR to NYC, shedding new light on the foundations of a particular ethnomedical system.

The Antillean genus Leptocereus represents an in-situ radiation among the Greater and Lesser Antilles of 19 currently recognized species. Extensive fieldwork carried out in the Dominican Republic over recent years has revealed that the species limits of Leptocereus of Hispaniola are more complex than previously thought. There are four currently recognized species that occur on the island, L. demissus, L. paniculatus, L. undulosus and L. weingartianus. We evaluate species limits in this group based on DNA sequence data and phylogenetic analysis, morphological characters and a survey of herbarium specimens from across Hispaniola. Based on our analyses, it is clear that at least five species occur on the island of Hispaniola, with the new species from Sierra de Bahoruco, L. velozianus, described here. We provide an identification key, distribution maps and photographic plates for all species on Hispaniola based on our own fieldwork and the study of herbarium specimens. The description of yet another species of Leptocereus on Hispaniola reiterates the importance of the poorly studied, but yet biodiverse, seasonally dry tropical forest in the Antilles.

Pseudophoenix ekmanii is a threatened palm species endemic to the Dominican Republic. Sap from trees is extracted to make a local drink; once they are tapped the individual usually dies. Plants are also illegally harvested for the nursery trade and destroyed by poachers hunting the endemic and threatened Hispaniolan parrot. We used 7 DNA microsatellite markers to assist land managers in developing conservation strategies for this palm. We sampled 4 populations along the known distribution range of this species (3 populations from the mainland and 1 from the small island of Isla Beata), for a total sample of n = 104. We found strong evidence for genetic drift, inbreeding, and moderate gene flow (i.e., all populations had at least 4 loci that were not in Hardy-Weinberg equilibrium, at least 9 loci pairs were in linkage disequilibrium, the pairwise F(ST) values ranged from 0.069 to 0.266, and had positive F(IS) values). Data supported an isolation-by-distance model, and cluster analyses based on genetic distances resolved 2 groups that match a north-south split. The population from Isla Beata had the lowest levels of genetic diversity and was the only one in which we found pairs of individuals with identical shared multilocus genotypes.