Pedro Lage Viana

Amazon plant diversity revealed by a taxonomically verified species list

Significance Large floristic datasets that purportedly represent the diversity and composition of the Amazon tree flora are being widely used to draw conclusions about the patterns and evolution of Amazon plant diversity, but these datasets are fundamentally flawed in both their methodology and the resulting content. We have assembled a comprehensive dataset of Amazonian seed plant species from published sources that includes falsifiable data based on voucher specimens identified by taxonomic specialists. This growing list should serve as a basis for addressing the long-standing debate on the number of plant species in the Amazon, as well as for downstream ecological and evolutionary analyses aimed at understanding the origin and function of the exceptional biodiversity of the vast Amazonian forests. Recent debates on the number of plant species in the vast lowland rain forests of the Amazon have been based largely on model estimates, neglecting published checklists based on verified voucher data. Here we collate taxonomically verified checklists to present a list of seed plant species from lowland Amazon rain forests. Our list comprises 14,003 species, of which 6,727 are trees. These figures are similar to estimates derived from nonparametric ecological models, but they contrast strongly with predictions of much higher tree diversity derived from parametric models. Based on the known proportion of tree species in neotropical lowland rain forest communities as measured in complete plot censuses, and on overall estimates of seed plant diversity in Brazil and in the neotropics in general, it is more likely that tree diversity in the Amazon is closer to the lower estimates derived from nonparametric models. Much remains unknown about Amazonian plant diversity, but this taxonomically verified dataset provides a valid starting point for macroecological and evolutionary studies aimed at understanding the origin, evolution, and ecology of the exceptional biodiversity of Amazonian forests.

Cambajuva (Poaceae: Bambusoideae: Bambuseae: Arthrostylidiinae), a New Woody Bamboo Genus from Southern Brazil

Abstract Arthrostylidiinae are one of the three subtribes of Neotropical woody bamboos and comprise 13 genera and over 160 described species. Recent phylogenetic analyses have demonstrated both the non-monophyly of Aulonemia Goudot and the sister relationship of Aulonemia ulei (Hack.) McClure to the monotypic Glaziophyton Franch., with which it forms a clade sister to the reminder of the subtribe. Based on these data and on morphological and anatomical characters, we present herein the new monotypic genus Cambajuva, as well as a new combination, to accommodate A. ulei. Morphological and anatomical descriptions are also provided, as well as a comparison with putatively related genera of the subtribe.

Two New Species of Borreria (Rubiaceae) from Brazil, with New Distributional Records for Pará State and a Key to Species with Transversally Sulcate Seeds

Two new species of the genus Borreria, B. carajasensis E.L. Cabral & L.M. Miguel and B. elaiosulcata E.L. Cabral & L.M. Miguel, are described and illustrated, based on material collected from iron outcrops in the Serra dos Carajás region, Pará State, Brazil. A key to morphologically similar species is provided; these species can be recognized by their transversally sulcate seeds. Borreria cupularis and B. multiflora are reported for the first time from the Pará State.

A New Woody Bamboo (Poaceae, Bambusoideae) from Central Brazil, Aulonemia xerophylla

Abstract.  A new species of Aulonemia Goudot (Poaceae) is formally described here from the Distrito Federal and Goiás in central Brazil. Aulonemia xerophylla P. L. Viana & Filg., known from gallery forests in the Cerrado, has deflexed and coriaceous leaf blades and awnless spikelets as diagnostic characters. Descriptions and illustrations of macro-morphological and anatomical characters of the new species are provided, as well as comments on its IUCN conservation status of Endangered (EN). Resumo.  Uma nova espécie de Aulonemia Goudot (Poaceae), nativa do Distrito Federal e Goiás, Brasil, é aqui formalmente descrita. Aulonemia xerophylla P. L. Viana & Filg., conhecida de matas de galeria em Cerrado no Brasil central, possui, como caracteres diagnóticos, lâminas foliares coriáceas e deflexas e espiguetas múticas. São apresentadas descrições e ilustrações de caracteres mofológicos e anatômicos da nova espécie assim como seu status de conservação, ameaçada, de acordo com os critérios da IUCN.

Overview of the systematics and diversity of Poales in the Neotropics with emphasis on the Brazilian flora

Poales represents a major part of Angiosperm and Monocot diversity. The families encompass ca. 20,000 species which is about 7% of the Angiosperms and 33% of the Monocots. Bromeliaceae, Cyperaceae, Eriocaulaceae, Juncaceae, Mayacaceae, Poaceae, Rapateaceae, Thurniaceae, Typhaceae, and Xyridaceae are the families represented in the Neotropics. In general terms some areas in the Neotropics could be considered hotspots for Poales with a high number of species in several genera and several centers of endemism – the Guayana Shield, Espinhaco Range and Atlantic Forest are highly diverse in Poales. In terms of the Brazilian flora, the order is well represented in the entire country with almost 4,400 species. It represents more than 50% of the total number of species of Monocotyledons in Brazil. The main goal here is to summarize the available information and provide an overview of the Poales in the Neotropics. The state of knowledge for each family, focused on the Brazilian flora, is provided and reinforces the importance of new studies in key-groups looking beyond the understanding of their diversity on the continent but also the conservation of the species.

Xyridaceae of Viruá National Park, Roraima state, Brazil

A taxonomic treatment of the Xyridaceae in the Virua National Park is presented. Located in Roraima state, northern Brazil, the park comprises a mosaic of lowland vegetation types, including forests, wetlands, and one of the largest continuous areas of campinarana in the Brazilian Amazon Basin. Xyridaceae are represented in the park by 20 species in the genera Abolboda and Xyris. Although the four species of Abolboda are widespread, most of the Xyris species (75%) are endemic to Amazonian open vegetation formations, such as campinaranas and savannas. This study was based on field, herbarium, and scanning electron microscopy research. The taxonomic treatment includes identification keys to the genera and species, morphological descriptions, SEM images of seeds for Xyris species, iconography, geographic distribution and comments on the ecology of the species. The poorly known Xyris connosepala is synonymized in Xyris guianensis.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Poaceae

This work presents a taxonomic treatment for the Poaceae in the canga of the Serra dos Carajas, Para state, Brazil. The article was prepared according to the guidelines of the project Flora of the canga of the Serra dos Carajas, based on the study of the specimens from the herbaria BHCB, MG and UB. A total of 87 species belonging to 37 genera were inventoried. Among these, Axonopus carajasensis, Paspalum cangarum, P. carajasense and Sporobolus multiramosus are considered endemic to the canga of the Serra dos Carajas; two new species are to be published soon (one of Paspalum and one of Hildaea); and one species of Trichanthecium is under study to determine its taxonomic identity. Six species are recorded for the first time in Para state. Morphological descriptions, identification keys, illustration of the spikelets, photo plates, detailed geographic distribution and diagnostic comments are provided for all species treated.

Flora of the canga of the Serra dos Carajás, Pará, Brasil: Sapindaceae

This study consists of a floristic survey of the Sapindaceae species in the iron rock outcrops of the Serra dos Carajás, Pará, Brazil. Identification keys, morphological descriptions, illustrations, geographical distribution and taxonomic comments are provided for the species. The family is represented by three genera and 11 species: Allophylus latifolius, A. racemosus, A. semidentatus, A. strictus, Matayba guianensis, M. inelegans, M. spruceana, S. confertiflora, S. caracasana, S. fuscifolia e S. lethalis, with A. semidentatus and S. lethalis being new occurrences for the state of Pará.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Melastomataceae

Apresenta-se um tratado taxonomico para a familia Melastomataceae nas areas de cangas da Serra dos Carajas. Foram registradas 42 especies distribuidas em 18 generos, sendo Miconia o mais rico, com 20 especies, seguido de Clidemia com tres especies. O genero monotipico Brasilianthus (B. carajensis) e considerado endemico da regiao de Carajas, assim como uma especie de Pleroma. Este trabalho apresenta descricoes morfologicas, chaves de identificacao para generos e especies, ilustracoes, distribuicao geografica e comentarios para as especies tratadas.

Buchnera carajasensis (Orobanchaceae), a new species from the canga vegetation of the Serra dos Carajás, Pará, Brazil

SummaryBuchnera carajasensis is described and illustrated. Information on its conservation status, taxonomy, habitat, geographic distribution, and phenology, along with a key to the Buchnera species found in Pará, is provided. The new species had previously been confused with B. tenuissima, a Mexican species, and is also similar to B. palustris, but exhibits differences in the inflorescence shape, in the indumentum, and in reproductive traits. The new species is apparently endemic to ironstone outcrops of the Serra dos Carajás, northern Brazil, and is assessed as Endangered in accordance with the IUCN criteria.