Agradecimentos: This work was only made possible through the kind support and cooperation of many people and institutions. The authors would like to thank the FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP (Fapesp processes 2009/ 14266-7 and 2011/22498-5) and the COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES (Capes) for the PhD. grants awarded to the first author. We are specially grateful to Fapesp for the international grant provided to to first author that allowed an one year interchange at the Royal Botanic Gardens, Kew. We are grateful to libraries’ staff that helped us to locate all the botanical literature necessary for this work, but specially the librarians of the State University of Campinas and Royal Botanic Gardens, Kew. A large number of researchers helped us to find rare papers and we are also grateful to them, with special reference to Professor Maria Jesus Nogueira Rodal. Most of the taxonomic positions adopted here follow the "Lista de Espécies da Flora do Brasil" database (http:// floradobrasil.jbrj.gov.br/), but some two hundred names presented here (mostly synonyms or misapplied names) were not available in the Lista do Brasil and we had to consult taxonomists in order to determine the status of each name. We are grateful to the taxonomists who shared their knowledge in order to make this catalogue possible: Alessandro Rapini (Apocynaceae), Alexa Araujo de Oliveira Paes Coelho (Portulacaceae), Ana Luiza Andrade Côrtes (Acanthaceae), Ana Maria Azevedo Tozzi (Fabaceae), Anderson Ferreira P. Machado (Cannabaceae), André M. Amorim (Malpighiaceae), Cyl Farney Catarino-De-Sá (Nyctaginaceae), Daniela Santos Carneiro-Torres (Euphorbiaceae), Daniela Zappi (Rubiaceae), Eduardo Gomes Gonçalves (Araceae), Efigênia de Melo (Polygonaceae), Elnatan Bezerra de Souza (Rubiaceae), Fátima Regina G. Salimena (Verbenaceae), Gerleni Lopes Esteves (Malvaceae), Gordon C. Tucker (Cyperaceae), Gustavo Hiroaki Shimizu (Vochysiaceae), Gwilym P. Lewis (Fabaceae), Jair Eustáquio Quintino de Faria Júnior (Myrtaceae), Jefferson Prado (Pteridophytes), João B. Baitello (Lauraceae), João Marcelo Alvarenga Braga (Menispermaceae), José Floriano Pastore (Polygalaceae), José Rubens Pirani (Anacardiaceae), Julie Dutilh (Liliaceae), Julio A. Lombardi (Vitaceae), Leonardo Biral (Celastraceae), Lúcia G. Lohmann (Bignoniaceae), Luciana dos Santos Dias de Oliveira (Euphorbiaceae), Luciano Paganucci de Queiroz (Fabaceae), Ludovic Jean Charles Kollmann (Begoniaceae), Luisa Senna (Amaranthaceae), M. Fátima Araújo (Euphorbiaceae), Marcelo Monge Egea (Asteraceae), Marccus Alves (Cyperaceae), Márcio Lacerda Lopes Martins (Euphorbiaceae), Marco O. Pellegrini (Commelinaceae, Araceae), Marcos Sobral (Myrtaceae), Margareth Ferreira de Sales (Euphorbiaceae), Maria Carolina Abreu (Oxalidaceae), Maria de Fátima Agra (Solanaceae), Maria Iracema Bezerra Loiola (Erythroxylaceae), Maria Mercedes Arbo (Turneraceae), Maria Salete Marchioretto (Amaranthaceae), Maria Stapf (Boraginaceae), Marlon Machado (Cactaceae), Massimo Bovini (Malvaceae), Nicholas Hind (Asteraceae), Pedro Fiaschi (Araliaceae), Raquel Fernandes Monteiro (Bromeliaceae), Raymond Harley (Lamiaceae), Regina Célia de Oliveira (Poaceae), Renato Goldenberg (Melastomataceae), Ricardo S. Couto (Dioscoreaceae), Rodrigo A. Camargo (Fabaceae), Rodrigo Sampaio Rodrigues (Poaceae), Ronaldo Marquete (Salicaceae), Rosangela Simão Bianchini (Convolvulaceae), Sérgio Romaniuc Neto (Cannabaceae), Shirley Graham (Lythraceae), Silvana Vieira (Marantaceae), Tânia R.S. Silva (Verbenaceae), Terry Pennington (Meliaceae, Sapotaceae), Victor Martins Gonçalez (Malvaceae), Vinicius Castro Souza (Plantaginaceae), Xavier Cornejo (Capparaceae). We would like to thank also Christine Barker from IPNI, who helped to determine the correct spelling of some names misspelled in papers and to determine whether some names were nomina nuda or misspelled names. We did our best to update the names to reflect the best taxonomic information available to us, but given the broad scope of the catalogue some changes may have been overlooked. Any mistakes that remain are authors’ Ver menos

Abstract: A catalogue is presented of plant names in use in the Caatinga Phytogeographical Domain (CPD), the largest semiarid ecoregion of South America. We compiled all pubished papers we could locate with floristic and/or phytosociological data relating to the CPD and created a database of all site-based surveys, all names reported in these surveys and the basic ecological data associated with each species. We then mapped the names used in survey reports to those currently accepted in Brazil, consulting specialists to resolve taxonomic and nomenclatural issues before synthesizing the data in order to present here a list of all names in use. Thus this compilation represents the taxonomic data in use by generalist botanists on a sub continental scale. Synthesizing the previously dispersed ecological data available for the species, we explored general ecological patterns in the CPD. We also classified each survey as documenting the flora of a specific type of environment within the CPD and compared the general floristic resemblance between different environments within CPD on a biogeographical scale. Rarefaction curves and species richness estimator indices were employed in order to address the question as to whether or not the Caatinga Phytogeographical Domain can be described as wellsampled. To date over 1700 species have been reported in site-based floristic and phytosociological studies in the CPD. Most surveys focused only on woody plants, ignoring the non woody component, but we show here that a large proportion of the plant biodiversity in the Caatinga is comprised of non woody plants. We estimate that 40% of the existing species were not sampled by site-based surveys. Moreover, most of the species in our database were recorded from a single site, while a few species were considered widespread. When comparing the number of widespread species in our dataset to results published for the cerrado savannas, we show that species in Caatinga seems to have a much more restricted distribution than plants in the Cerrado. We present here a catalogue of all plant names recorded and discuss sampling and geographical issues related to the floristic study of Caatinga Ver menos