Seasonally dry tropical forests are distributed across Latin America and the Caribbean and are highly threatened, with less than 10% of their original extent remaining in many countries. Using 835 inventories covering 4660 species of woody plants, we show marked floristic turnover among inventories and regions, which may be higher than in other neotropical biomes, such as savanna. Such high floristic turnover indicates that numerous conservation areas across many countries will be needed to protect the full diversity of tropical dry forests. Our results provide a scientific framework within which national decision-makers can contextualize the floristic significance of their dry forest at a regional and continental scale. N eotropical seasonally dry forest (dry forest) is a biome with a wide and fragmented distribution, found from Mexico to Argentina and throughout the Caribbean (1, 2) ( Fig. 1). It is one of the most threatened tropical forests in the world (3), with less than 10% of its original extent remaining in many countries (4).Following other authors (5, 6), we define dry forest as having a closed canopy, distinguishing it from more open, grass-rich savanna. It occurs on fertile soils where the rainfall is less thañ 1800 mm per year, with a period of 3 to 6 months receiving less than 100 mm per month (5-7), during which the vegetation is mostly deciduous. Seasonally dry areas, especially in Peru and Mexico, were home to pre-Columbian civilizations, so human interaction with dry forest has a long history (8). The climates and fertile soils of dry forest regions have led to higher human population densities and an increasing demand for energy and land, enhancing degradation (9). More recently, destruction of dry forest has been accelerated by intensive cultivation of crops, such as sugar cane, rice and soy, or by conversion to pasture for cattle.Dry forest is in a critical state because so little of it is intact, and of the remnant areas, little is protected (3). For example, only 1.2% of the total Caatinga region of dry forest in Brazil is fully protected compared with 9.9% of the Brazilian Amazon (10). Conservation actions are urgently needed to protect dry forest's unique biodiversity-many plant species and even genera are restricted to it and reflect an evolutionary history confined to this biome (1).We evaluate the floristic relationships of the disjunct areas of neotropical dry forest and highlight those that contain the highest diversity and endemism of woody plant species. We also explore woody plant species turnover across geographic space among dry forests. Our results provide a framework to allow the conservation significance of each separate major region of dry forest to be assessed at a continental scale. Our analyses are based on a subset of a data set of 1602 inventories made in dry forest and related semi-deciduous forests from Mexico and the Caribbean to Argentina and Paraguay that covers 6958 woody species, which has been compiled by the Latin American and Caribbean Seasonally Dry Tropica...

The pantropical genus Begonia is the sixth-largest genus of flowering plants, including 1870 species. The sections of Begonia are used frequently as analogues to genera in other families but, despite their taxonomic utility, few of the current sections have been examined in the light of molecular phylogenetic analyses. We present herein the largest, most representative phylogeny of Begonia published to date and a subsequent provisional sectional classification of the genus. We utilised three plastid markers for 574 species and 809 accessions of Begonia and used Hillebrandia as an outgroup to produce a dated phylogeny. The relationships between some species and sections are poorly resolved, but many sections and deeper nodes receive strong support. We recognise 70 sections of Begonia including 5 new sections: Astrothrix, Ephemera, Jackia, Kollmannia, and Stellandrae; 4 sections are reinstated from synonymy: Australes, Exalabegonia, Latistigma and Pereira; and 5 sections are newly synonymised. The new sectional classification is discussed with reference to identifying characters and previous classifications.

Summary Pullan, M. R., Watson, M. F., Kennedy, J. B., Raguenaud, C. & Hyam, R.: The Prometheus Taxonomic Model: a practical approach to representing multiple classifications. – Taxon 49: 55‐75. 2000. – ISSN 0040‐0262. A model for representing taxonomic data in a flexible and dynamic system capable of handling and comparing multiple simultaneous classifications is presented. The Prometheus Taxonomic Model takes as its basis the idea that a taxon can be circumscribed by the specimens or taxa of lower rank which are said to belong to it. In this model alternative taxon concepts are therefore represented in terms of differing circumscriptions. This provides a more objective way of expressing taxonomic concepts than purely descriptive circumscriptions, and is more explicit than merely providing pointers to where circumscriptions have been published. Using specimens as the fundamental elements of taxon circumscription also allows for the automatic naming of taxa based upon the distribution and priority of types within each circumscription, and by application of the International Code of Botanical Nomenclature. This approach effectively separates the process of naming taxa (nomenclature) from that of classification, and therefore enables the system to store multiple classifications. The derivation of the model, how it compares with other models, and the implications for the construction of global data sets and taxonomic working practice are discussed.

Digitisation programmes in many institutes frequently involve disparate and irregular funding, diverse selection criteria and scope, with different members of staff managing and operating the processes. These factors have influenced the decision at the Royal Botanic Garden Edinburgh to develop an integrated workflow for the digitisation of herbarium specimens which is modular and scalable to enable a single overall workflow to be used for all digitisation projects. This integrated workflow is comprised of three principal elements: a specimen workflow, a data workflow and an image workflow.The specimen workflow is strongly linked to curatorial processes which will impact on the prioritisation, selection and preparation of the specimens. The importance of including a conservation element within the digitisation workflow is highlighted. The data workflow includes the concept of three main categories of collection data: label data, curatorial data and supplementary data. It is shown that each category of data has its own properties which influence the timing of data capture within the workflow. Development of software has been carried out for the rapid capture of curatorial data, and optical character recognition (OCR) software is being used to increase the efficiency of capturing label data and supplementary data. The large number and size of the images has necessitated the inclusion of automated systems within the image workflow.

A model for representing taxonomic descriptive data is presented. The model has been developed in response to the growing requirement for the global exchange of descriptive data. Meaningful exchange of data requires that data be represented in a form that can be consistently parsed and interpreted, requiring a common data model and the constrained and explicitly defined use of descriptive terms. The model presented here is divided into two parts that address both of these issues. A new data model for the representation and storage of taxonomic descriptive data is proposed that builds on and extends the best features of current descriptive data models and formats. An ontology‐based model for defining and constraining the use of descriptive terms is also presented. The model is based on an analysis of current taxonomic working practices and the processes involved in generating a description. The model takes a specimen‐oriented approach allowing descriptive data to be represented through a range of levels of abstraction from actual measurements of structures on a specimen to abstract descriptions of the features expected to be found on a specimen that is a member of a particular taxon. A comparison and discussion of the important aspects of the new model relative to existing models is presented.