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Aim: Factors affecting bromeliad distribution depend on the life forms of the studied species; some could grow as terrestrial, saxicolous, or epiphytic depending on the type of habitat. We analysed the distribution patterns of the life forms of a bromeliad species in different biogeographic domains and associated them with environmental variables and vegetation types. Location: Chaquenian, Amazonian, and Seasonally Dry Tropical Forest domains; South America. Taxon: The tank bromeliad Aechmea distichantha (Bromeliaceae: Bromelioideae). Methods: We compiled records of the biogeographic distribution and the vegetation types where A. distichantha occurs based on bibliographic data, digital datasets, herbaria, and personal observations. We associated the distributional records of this species with altitude, five selected bioclimatic variables, four soil variables, and with the vegetation types where it occurs. Results: A. distichantha has been recorded as epiphytic, terrestrial and saxicolous in all biogeographic domains but showed contrasting patterns in life form proportions among them. In the Amazonian domain, characterized by evergreen tropical and subtropical forests with high precipitation, it mainly grows as epiphytic. In the Chaquenian domain, dominated by xerophytic forests with low rainfall, high soil pH and base saturation, it mainly grows as terrestrial, whereas in the Seasonally Dry Tropical Forest domain, the three life forms were recorded in similar proportions. In azonal plant communities of all domains, it mainly grows as saxicolous. Main Conclusions: This tank bromeliad species can thrive in sites with contrasting habitat and environmental conditions. Its ability to survive in different environments could be associated with its high frost tolerance, the presence of the CAM photosynthetic pathway, a well‐developed phytotelma, and high phenotypic plasticity. The life form prevailing in each domain is influenced by water availability (i.e., the quantity of water available during each year, the precipitation in the driest month, and the plant water supply relative to demand). [ABSTRACT FROM AUTHOR]

Background and aims: Ruprechtia apetala (Polygonaceae) is a woody Chaquenian species with large morphological variability throughout its distribution range. The present study attempts to evaluate this variability within Argentina. M&M: Forty-two individuals were collected from six Argentinian provinces, corresponding to the regions of Sierra Chaco, Piedmont Forest and the transition zone between them. Numerous morphological characters, both reproductive and vegetative, were analyzed. Principal Components and Conglomerates Analysis were performed, in order to establish the existence of morphogroups; the latter were evaluated by univariate analysis (Kruskal-Wallis test and cluster description by R) and multivariate (ANOSIM and PERMANOVA), to detect possible significant intraspecific differences. Additionally, a distribution map of the collected specimens was drawn up. Results: From the multivariate analysis two morphological groups were detected, mainly at foliar and growth habit levels. The ANOSIM and PERMANOVA analysis show a significant global difference among both groups (p-value < 0,05); however, the corresponding statistics indicate a high similarity between them. Additionally, it was demonstrated that no characters are mutually exclusive to either group. Conclusions: Observed morphological differences between specimens from different biogeographical regions, though not mutually exclusive, allow postulating the existence of ecotypes within the species. [ABSTRACT FROM AUTHOR]

The eastern Formosa forests of Argentina, belonging to Eastern Chaco District, are distributed following a gradient from the watercourse levee where the 'Bosque Ribereño' is placed, through an intermediate zone where the so-called 'Bosque Transicional' develops, up to the topographically lower zone where the 'Monte Fuerte' forest is located. It has been postulated that the distribution of woody species amongst these three types of forests could be explained by their ability to survive to different stress conditions of water availability. In such context, it is proposed that, to the seedling status, that capacity could differ between species belonging to these forests, related to the topographic height of them. The tolerance to 'restricted watering' and 'flooding' controlled conditions in seedlings of eight selected woody species, (Peltophorum dubium, Enterolobium contortisiliquum, Gleditsia amorphoides, Microlobius foetidus, Diplokeleba floribunda, Caesalpinia paraguariensis, Prosopis nigra and Schinopsis balansae) belonging to the three forest types, was experimentally evaluated in this contribution. The results showed that the seedlings of all species were less tolerant to flooding prolonged conditions than to the 'drought' (restricted watering) level applied. None of them was affected in terms of growth under the 'restricted watering' treatment. In this way, the hypothesis could not be validated, nevertheless it is considered that such answer could be related to the fact these woody species usually thrive in the Seasonally Dry Tropical Forests domain. [ABSTRACT FROM AUTHOR]

Nomenclatural notes in the genus Schinopsis (Anacardiaceae). During the monographic study of the genus Schinopsis (Anacardiaceae) a nomenclatural revision of its species and synonyms was performed. The names Schinopsis brasiliensis, S. brasiliensis var. glabra, S. heterophylla, S. marginata, and S. peruviana are lectotypified, and some cases of inadvertent lectotypifications in previous works are indicated. An epitype for S. haenkeana, entity so far considered doubtful, is designated. [ABSTRACT FROM AUTHOR]

This paper records for the first time the presence in the Argentine flora of the small tree Cynophalla polyantha (Triana & Planch.) Cornejo & Iltis (Capparaceae), which was recently found in the north of the province of Salta, close to the Bolivian border. [ABSTRACT FROM AUTHOR]

Existe en Sudamérica un patrón de distribución altamente coincidente entre las diferentes especies de leñosas arbóreas de los bosques estacionalmente secos, que atraviesa el continente en forma de herradura o arco desde las Caatingas del NE del Brasil, atraviesa el sector de las antiguas misiones jesuíticas de Brasil, Paraguay y Argentina, la Chiquitanía boliviana, el Bosque Pedemontano Subandino del SW de Bolivia y NW de Argentina, e incluye algunos valles secos interandinos de Bolivia y Perú. Se ha propuesto establecer a esta distribución fragmentaria y disyunta de Bosques Secos Estacionales Neotropicales (BSEN) como un nuevo Dominio fitogeográfico, con el árbol Anadenanthera colubrina (Mimosoideae, Fabaceae) como su especie más paradigmática. El concepto actual de los BSEN abarca tipos de vegetación leñosa correlacionados con una fuerte estacionalidad climática en los trópicos de Sudamérica, con una estación seca bien definida pero de duración muy variable. El vínculo más fuerte entre los BSEN es su composición florística, lo cual ha sido demostrado tanto analizando los patrones de distribución biogeográfica de sus especies leñosas más importantes como comparando su vegetación (con análisis fitosociológico clásico y por análisis numérico). Esta nueva interpretación de los BSEN conduce a varias derivaciones con impactos biogeográficos (Teoría del Arco Pleistocénico), evolutivos (con estudios recientes a nivel molecular) y con impacto en otras ciencias (v.g. Zoología). Los BSEN han recibido poca atención de conservacionistas comparado con bosques tropicales lluviosos. Se realiza un urgente llamado a la preservación de sus recursos genéticos y de biodiversidad. [ABSTRACT FROM AUTHOR]

Some aspects of morphology, taxonomy and nomenclature about Monvillea phatnosperma (K. Schum.) Britton & Rose (Cactaceae), a species native from the north of the 'Great Chaco' and adjacent areas, are considered. M. phatnosperma var. arenasii var. nov. is described and ilustrated in replacement of Monvillea kroenleinii R. Kiesling -nom. inval. [ABSTRACT FROM AUTHOR]

The genus Celtis L. (Cannabaceae) comprises around 73 species distributed in temperate and tropical regions of both hemispheres. Most South American species belong to the subgenus Mertensia Planch., and they are characterized by showing high morphological plasticity. A recent taxonomic revision of this group was carried out with an excessively reductionist criterion regarding the number of accepted species and that does not clearly reflect the morphological differences among them. In order to contribute to the correct delimitation of the specific entities, a morpho-descriptive approach is presented for ten taxa of the genus Celtis (C. brasiliensis, C. chichape, C. clausseniana, C. fluminensis, C. pallida var. pallida, C pallida var. discolor, C. serratissima, C. spinosa, C. spinosissima and C. tala) growing in South American Southern Cone. The morphology was analyzed through the use of a stereomicroscope and/or the tpsDig program for digital images of specimens. As a result, a key is provided for the determination of the aforementioned species and a detailed morphological description of the vegetative (habit, bark, branches, spines, brachyblasts, indumentum and leaves) and reproductive structures (inflorescences, flowers, fruits and endocarp -pyrene-). In addition, a specimen collection guide is proposed with a list of the main morphological characters that should be observed in the field, to facilitate future identifications. [ABSTRACT FROM AUTHOR]

The Gran Chaco is a wide ecologic-geographic region comprising northern Argentina, western Paraguay, southern Bolivia and the southwestern extreme of Brazil. This region exhibits extreme temperatures, annually regular frosts, and sedimentary soils; it has been dramatically threatened by agriculture expansion in recent decades. Therefore, increasing knowledge of plant diversity is critical for conservation purposes. We present a Legume checklist of the Gran Chaco ecoregion including conservation status of its endemic species. Leguminosae is the third most diverse plant family in the Neotropics. Assuming a rigorous spatial definition of the Gran Chaco, we recorded 98 genera, 362 species, and 404 specific and infraspecific taxa. Endemic/typical taxa were 17%, comparable to adjacent tropical plant formations, and they were found in higher percentages in Caesalpinioideae (24%) and Cercidoideae (33%) than Papilionoideae (11%) subfamily. We also analyzed the plant diversity comparing lineages and subregions. The Gran Chaco Legumes are predominantly widespread generalists, or they belong to either Chaco sensu stricto or Neotropical Seasonally Dry Tropical Forest (SDTF) lineages. Though the Humid Chaco registered the highest species richness, Dry Chaco and Sierra Chaco, the most threatrened subregions, exhibited the highest percentages of exclusive and proper Chaco-lineage species. These results suggest that diversification of Legumes has been most relevant in Dry Chaco and Sierra Chaco, probably by their more demanding and harsh environmental conditions limiting the dispersion of generalists or intrusive-invading species. This study is paramount to reach an improved delimitation of the Gran Chaco ecoregion in transitional areas with the SDTF and Cerrado formations. Conservation status is critical in genera of high economic interest, such as Arachis, Mimosa and Prosopis. At least one third of endemic taxa exhibit a critical status of conservation or are endangered, many of them being relevant to inbreeding program or exhibiting multiple economic uses. [ABSTRACT FROM AUTHOR]