William Wayt Thomas

Angiospermas em remanescentes de floresta montana no sul da Bahia, Brasil

A floristic study of three areas of montane Atlantic forest in southern Bahia, Brazil, was carried out. From 2004 to 2008 regular botanical collections were made, principally along trails in the interior of the forest fragments at: the Reserva Serra da Pedra Lascada (SPL), the Reserva Serra das Lontras (SLO) and the Reserva Particular do Patrimonio Natural Serra Bonita (SBO). The species richness of each area was compared to that of the other two, and together to other areas of Atlantic coastal forest in Bahia and southeastern Brazil. For all three areas, a total of 1129 species in 467 genera and 124 families were found. Trees represented 46.9% of the species, followed by herbs (20.1%), epiphytes (19.5%), and vines and lianas (13.5%). The families Araceae, Asteraceae, Bromeliaceae, Fabaceae, Lauraceae, Melastomataceae, Myrtaceae, Orchidaceae, Piperaceae, Poaceae, Rubiaceae, and Solanaceae showed the highest species richness for the three areas together. The genus Psychotria (Rubiaceae) had the highest number of species for all three areas (21 spp.), followed by Miconia (20 spp.), Solanum (20 spp.), Piper (19 spp.), Ocotea (16 spp.), Leandra (16 spp.), Peperomia (15 spp.), and Myrcia (14 spp.). The results confirm the high species diversity of angiosperms in southern Bahia and demonstrate for the first time the presence of species characteristic of montane regions of southeastern Brazil in this region.

Aplicações taxonômicas da anatomia foliar das espécies brasileiras de Hypolytrum Rich. (Cyperaceae)

Hypolytrum Rich. (subfamily Mapanioideae) has a pantropical distribution being represented in the Neotropics by 16-21 species, most of them growing in several Brazilian ecosystems. Informations from foliar anatomy was analysed for 10 species of the genus. The most useful characters detected in Hypolytrum species studied here are: the shape of the leaves in cross section, the occurrence of granules (probably formed by silica) on the epidermal cells; features of the cuticle, the hypoderm and the aerenchymatous parenchyma; the number of layers and origin (hypodermal and epidermal) of bulliform cells; the presence of papillae on the abaxial face of the epidermis; and occurence of radiate parenchyma on the smaller bundles. Studies of foliar anatomy showed to be useful in generic and specific delimitation but do not support the taxonomic sections established.

The American genera of Simaroubaceae and their distribution

A review of the phylogenetic relationships of the subfamilies of Simaroubaceae is presented and the distribution patterns of the American genera are discussed. Englers six subfamilies are evaluated and the three subfamilies represented in the Americas and their included genera are discussed in detail. The eight American genera fall into three broad distributional categories: widely distributed throughout the neotropics, limited to northern South America, and disjunct between the West Indies, Central America and Mexico and southern South America. These distributions are discussed and interpreted.

Anatomia do escapo e rizoma de espécies brasileiras de Bulbostylis Kunth (Cyperaceae)

Bulbostylis Kunth (subfamily Cyperoideae) comprises approximately 150 species with centers of distribution in South America and Africa. The anatomy of the scapes was studied in 40 species of Bulbostylis. The characters found to be of taxonomic value in the key species are: the shape of the scape in transverse section, the presence of ribs and furrows, the aspect of the epidermal cells and stomata, the shape of the cortical sclerenchymatous strands, the number of vascular unit, a fistulose medulla, and the occurrence of radiate parenchyma. These characters were found to be diagnostically useful at the specific level. We also show that the scape should be considered a monostele. The atactostele appears in the rhizome.

Floristic units and their predictors unveiled in part of the Atlantic Forest hotspot: implications for conservation planning

We submitted tree species occurrence and geoclimatic data from 59 sites in a river basin in the Atlantic Forest of southeastern Brazil to ordination, ANOVA, and cluster analyses with the goals of investigating the causes of phytogeographic patterns and determining whether the six recognized subregions represent distinct floristic units. We found that both climate and space were significantly (p ≤ 0.05) important in the explanation of phytogeographic patterns. Floristic variations follow thermal gradients linked to elevation in both coastal and inland subregions. A gradient of precipitation seasonality was found to be related to floristic variation up to 100 km inland from the ocean. The temperature of the warmest quarter and the precipitation during the coldest quarter were the main predictors. The subregions Sandy Coastal Plain, Coastal Lowland, Coastal Highland, and Central Depression were recognized as distinct floristic units. Significant differences were not found between the Inland Highland and the Espinhaço Range, indicating that these subregions should compose a single floristic unit encompassing all interior highlands. Because of their ecological peculiarities, the ferric outcrops within the Espinhaço Range may constitute a special unit. The floristic units proposed here will provide important information for wiser conservation planning in the Atlantic Forest hotspot.

125 years of floristic research and collecting at The New York Botanical Garden

As part of The New York Botanical Garden’s 125th anniversary, a summary of floristic research by NYBG staff is presented. The first 50 years of the Garden were extremely productive and resulted in floras covering most of the United States and Canada. The focus of research at the Garden shifted to the Neotropics and diversified, especially in northern South America and Brazil, and continues to thrive.

From evergreen to deciduous tropical forests: how energy–water balance, temperature, and space influence the tree species composition in a high diversity region

Background: Understanding floristic and geographic patterns in one of the most biodiverse regions in the world – the Atlantic forest of eastern Bahia, Brazil – can identify the drivers of diversity in tropical forests and provide useful information for biological conservation. Aims: To understand the role of both climate and geographical location on variation in tree species composition in a region characterised by an abrupt transition from wet forests to semi-arid thorn-woodlands. To test whether a regional classification of forests according to elevation belts and leaf flush pattern is consistent with floristic composition. Methods: We submitted 14,094 tree species occurrence records and 31 geo-climatic variables prepared for 57 sites in eastern Bahia, Brazil, to multivariate and regression analyses and variance partitioning. Results: Climate and space were both significantly (P ≤ 0.05) contributing to explaining floristic variations. Actual evapotranspiration, duration of water deficit, and minimum temperature of coldest month were the main predictors. Floristic differences were significant except when comparing evergreen lower plains and upper plains forests. Conclusions: Although distance among sites may play an important role, species composition is chiefly influenced by environmental gradients. This highlights environmental heterogeneity as a key factor in the planning of biodiversity conservation in tropical forests.

Hard Copy to Digital: Flora Neotropica and the World Flora Online

One of the greatest challenges in achieving the goals of the World Flora Online (WFO) will be to make available the huge amount of botanical information that is not yet available digitally. The New York Botanical Garden is using the Flora Neotropica monograph series as a model for digitization. We describe our efforts at digitizing Flora Neotropica monographs and why digitization of hardcopy descriptions must be a priority for the WFO project.

Micromorfologia da superfície do aquênio em Bulbostylis Kunth (Cyperaceae)

Bulbostylis comprises approximately 150 species distributed in the tropics and subtropics of both hemispheres. The morphology of the achene surface, using scanning electron microscopy, was used to differentiate 38 species of Bulbostylis Kunth (Cyperaceae) and revealed the presence of three patterns of ornamentation on the achene surface: tuberculate, reticulate, and transversely rugose. Other characters of taxonomic interest were also observed, including the primary sculpturing, the ornamentation of the anticlinal cell walls of the epidermis, the presence or absence of silica bodies, and the shape of the epidermal cells.

Simaba arenaria (Simaroubaceae): A New Species from Sandy Coastal Plains in Northeastern Brazil, with Notes on Seedling Morphology

Abstract In this paper we describe and illustrate a new species of Simaba from the sandy coastal plains in northeastern Brazil, and discuss the controversial limits of the three sections proposed in the genus by Englerian classification. Simaba arenaria has a restricted distribution: it is known only from two small, somewhat disturbed areas, in restinga vegetation of Bahia and Sergipe states. The evaluation of its threatened status indicates that it is an endangered taxon, according to the IUCN Red List categories and criteria. We also provide novel data on the seedling of this species.