Oliveira-Filho A.T.,Federal University of Minas Gerais |
Cardoso D.,State University of Feira de Santana |
Schrire B.D.,Herbarium Royal Botanic Gardens |
Lewis G.P.,Herbarium Royal Botanic Gardens |
And 4 more authors.
South African Journal of Botany | Year: 2013
Phylogenies of legume taxa are ecologically structured along a tropical seasonality gradient, which suggests phylogenetic niche conservatism. This seasonality gradient spans Neotropical wet forests, savannas, and highly seasonal drought-prone woody vegetation known as the succulent biome. Ecological phylogenetic structure was investigated using a community phylogenetic approach. We further analyzed bioclimatic and other independent variables that potentially explained phylogenetic beta diversity among 466 floristic sites that spanned the savanna and succulent biomes in eastern South America. Explanatory variables were selected using variance inflation factors, information criteria, and the ability to explain both species and phylogenetic beta diversity. A model involving annual precipitation suggests that a threshold of <. 1200. mm explains community phylogenetic structure along the savanna-succulent biome transition. Variables involving temperatures or measures of seasonality were notably lacking from top-ranked models. The abundance and diversity of legumes across the tropical seasonality gradient suggest that a high nitrogen metabolism confers an advantage in one of two ways, both of which are related to rapid growth rates. Legumes adapted to the succulent biome may be responding to regular post-dry-season leaf-flush opportunities. Legumes adapted to the savanna biome may be responding to intermittent post-disturbance growing opportunities. A seasonal predominance of leaf flushing by woody plants implicates the role of ecological stability in the succulent biome because of the need to recover the cost of regenerating short-lived leaves. Ecological stability may be the fundamental cause of ecological phylogenetic structure across the tropical seasonality gradient and required for maintaining high levels of both leaf-flushing legume and succulent plant biodiversity. © 2013 South African Association of Botanists.
Mwachala G.,East African Herbarium |
Cheek M.,Herbarium Royal Botanic Gardens
Nordic Journal of Botany | Year: 2012
Dracaena mokoko Mwachala & Cheek sp. nov. is described from the Mokoko forest in the western foothills of Mt Cameroon, in Cameroon, west Africa. Using the IUCN standard it is assessed as 'Critically Endangered' (CR) due to its small population size (less than 50 individuals are known), its small extent of occurrence, and threats from oil exploration and logging in the Mokoko forest. The new species is considered allied to D. aubryana Brongn. ex C. J. Morren of west-central Africa but differs in having spiralled leaves with the blade gradually narrowing into the petiole rather than distichous leaves in which there is an abrupt transition from the well-developed blade to the petiole. © 2012 The Authors. Nordic Journal of Botany © 2012 Nordic Society Oikos.
Silva M.F.S.,Federal University of Piauí |
De Andrade I.M.,Federal University of Piauí |
Mayo S.J.,Herbarium Royal Botanic Gardens
Botanical Journal of the Linnean Society | Year: 2012
Leaf characters of populations of the aquatic macrophyte Montrichardia linifera were studied using geometric morphometrics to compare variation with traditional circumscriptions of the two recognized species. Two hundred and ten individuals were sampled from seven populations in the delta region of the Rio Parnaíba, north-east Brazil. Six landmarks of the leaf blade were digitized from images and analysed with MorphoJ software. Procrustes-aligned configurations were studied using principal component analysis and canonical variates analysis in the pooled data and individual populations. Sinus shape variation was studied using landmark configurations of the posterior lobe basiscopic lamina. Covariation of leaf blade shape, basiscopic lamina shape, secondary vein number and petiole ligule length was investigated with partial least squares analysis. Allometry of these variables with leaf blade centroid size was investigated using multivariate regression, linear modelling and analysis of covariance. Measured variables varied continuously over the ranges previously reported for the two species. The characters of the two species morphotypes covaried and were only partly influenced by allometric effects. Symmetric shape variables predominated, but a distinctive left- and right-handed asymmetry occurred in all populations. Genetic and ecological studies are needed to investigate the significant inter-population differences further. The study offers a methodology for a broader combined morphometric/molecular investigation. © 2012 The Linnean Society of London.
Guimaraes P.J.F.,Institute Pesquisas Jardim Botanico Do Rio Of Janeiro |
Woodgyer E.M.,Herbarium Royal Botanic Gardens
Phytotaxa | Year: 2016
Tibouchina rosanae, a new species of Melastomataceae (Melastomeae) from the state of Mato Grosso, Brazil, is described, illustrated and compared to its putative closest allied. It is characterized mainly by the inflorescence that is lax. Tibouchina rosanae is an amphistomatic species, and the presence of stomata on the adaxial leaf surface is reported here for the first time in the genus. © 2016 Magnolia Press.
Cheek M.,Herbarium Royal Botanic Gardens |
Jebb M.,National Botanic Gardens
Willdenowia | Year: 2013
Nepenthes ramos Jebb & Cheek, sp. nov. is described and illustrated from Surigao Province, Mindanao, Philippines, and placed in the N. alata Blanco group. An updated key to the species of the group is provided. The new species is characterized by the subcylindric upper pitchers which are more or less equally wide at base and apex, only slightly and gradually constricted in the middle and lacking in fringed wings, and by the lower surface of the lid having a well-developed basal appendage almost lacking glands, the lid surface having dimorphic nectar glands, large perithecoid glands along the midline and much smaller non-perithecoid but bordered glands on the rest of the lid. The species is assessed as Critically Endangered using the IUCN 2001 standard. Logging and open-cast mining are thought to be threats to this species. © 2013 BGBM Berlin-Dahlem.