Scielo RSS <![CDATA[Acta Botanica Brasilica]]> http://www.scielo.br/rss.php?pid=0102-330620140001&lang=pt vol. 28 num. 1 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[<b>Lichenicolous fungi in Iğdır province, Turkey</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100001&lng=pt&nrm=iso&tlng=pt As a result of lichenological exploration in the province of Iğdır, Turkey, forty species of lichenicolous fungi belonging to eighteen genera were identified on twenty-seven different lichenized fungi. Four lichenicolous fungi-Arthonia protoparmeliopsidis, Lichenostigma radicans, L. subradians and Sclerococcum sphaerale-represent new records for Turkey. In addition, A. protoparmeliopsidis is new to Asia and Gemmaspora lecanorae was found for the second time on Aspicilia sp. Geographical distributions are also presented. <![CDATA[<b>New additions of coccoid green algae to the phycoflora of Brazil and the Neotropics</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100002&lng=pt&nrm=iso&tlng=pt The present study presents 11 new additions of coccoid green algae to the phycoflora of Brazil, including the first record of the genus Westellopsis for the neotropical region. Samples of periphyton and plankton were collected in two areas of the Marimbus Wetlands (the Marimbus do Baiano and Marimbus do Remanso, within the Marimbus-Iraquara Environmentally Protected Area), in the Chapada Diamantina Region of the state of Bahia, Brazil. Sample collection occurred during dry periods (April-June and August 2011) and rainy periods (October-December 2011 and February 2012). Here, we describe the taxa identified from the 56 samples collected. <![CDATA[<b>Desmids (Desmidiaceae, Zygnematophyceae) with cylindrical morphologies in the coastal plains of northern Bahia, Brazil</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100003&lng=pt&nrm=iso&tlng=pt Our knowledge of desmids with cylindrical morphologies in the state of Bahia, Brazil, is quite limited, only 13 such taxa having been described to date. The present study reports the results of a taxonomic inventory of desmids (Desmidiaceae) with cylindrical morphologies from the coastal plains of northern Bahia. During the summer months (January-March) and winter months (June-August) of two separate years (2007 and 2009), we collected a total of 90 samples of planktonic and periphytic material from lotic and lentic environments within three environmentally protected areas within the state (Rio Capivara, Lagoas de Guarajuba, and Litoral Norte). We identified 32 taxa, distributed among six genera (Docidium, Haplotaenium, Ichthyocercus, Pleurotaenium, Tetmemorus, and Triploceras); three were new additions to the algal flora of Brazil (Haplotaenium minutum var. minutum f. maius, Ichthyocercus angolensis, and Pleurotaenium coronatum var. nodulosum). In addition, the geographical distributions of 20 taxa were expanded to include northeastern Brazil. The genus Docidium was reported for the first time in Bahia. <![CDATA[<b>Architecture of tree species of different strata developing in environments with the same light intensity in a semideciduous forest in southern Brazil</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100004&lng=pt&nrm=iso&tlng=pt We aimed to answer the following questions related to the architecture of individuals 0.5-3.0 m in height belonging to understory or canopy/emergent layer tree species: "Is there a difference between individuals belonging to different strata developing in environments with the same light intensity, in terms of their architecture?"; and "Given the same light intensity, do understory species exhibit less crown plasticity than do canopy/emergent layer species?" Thirteen architectural variables were evaluated in 80 individuals per species. We found that understory species showed greater increases in stem thickness and leaf number, as well as wider, deeper crowns, longer branches, greater self-shading and less crown plasticity. Stems and crowns were more slender in the canopy species than in the understory species. These differences might be due to the trade-off between vertical and lateral growth. Our results indicate that, regardless of the group to which they belong, species are best able to take advantage of light conditions in the understory of the forest. However, because they demand more light, canopy species showed a growth form that resulted in an architecture that is likely to enable better light capture in the understory. <![CDATA[<b>Bryophyte flora in upland forests at different successional stages and in the various strata of host trees in northeastern Pará, Brazil</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100005&lng=pt&nrm=iso&tlng=pt In the northeastern region of the Brazilian state of Pará, approximately 90% of the forested areas are secondary forests. Secondary forests are interesting areas for floristic studies aimed at determining the effects that clear-cutting has on bryophyte communities. The aim of this study was to compare upland forests at different successional stages and the various strata of host trees, in terms of the bryophyte species composition. Bryophyte specimens were collected between August 2005 and September 2006 from host trees in primary and secondary forests of different ages and of different heights, within the municipality of Capitão Poço, in the state of Pará. The vertical distribution of bryophytes was evaluated in 15 host trees within the primary forest. We identified a total of 99 bryophyte species: 33 mosses and 66 liverworts. The dominant family was Lejeuneaceae, with 56 species. Most of the species (n = 60) had a neotropical distribution, and 3 species were endemic to Brazil. Cololejeunea minutissima var. myriocarpa (Nees & Mont.) R.M.Schust., Pycnolejeunea papillosa X.-L. He, Radula mammosa Spruce and Verdoornianthus marsupiifolius (Spruce) Gradst. represent new records for the state of Pará. In the successional forests evaluated, we identified 78 species, most of which (n = 38) occurred in primary forest. On the host tree trunks evaluated in the primary forest, we observed 31 species occurring at heights ranging from 2 m to 20 m. Despite the fact that secondary forests account for such a large proportion of the forested areas in Capitão Poço, we found that the bryoflora was relatively rich, comprising 31% of the species recorded for the state. The fact that 40% of the species recorded occurred exclusively in the secondary forests and the fact that 45.5% of the species recorded in primary forest occurred within the 2-20 m height range show the importance of studies focusing on bryophytes in secondary forests and in the upper strata of host trees in primary forests. <![CDATA[<b>Effects of ovule and seed abortion on brood size and fruit costs in the leguminous shrub <i>Caesalpinia gilliesii</i> (Wall. ex Hook.) D. Dietr</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100006&lng=pt&nrm=iso&tlng=pt For several plant species, brood size results from the abortion of ovules and seeds. However, these processes have rarely been studied together in wild plants. In some of the leguminous species studied, seed abortion has been found to depend on pollen quality and on the position of the ovule or fruit. The direct consequence for the mother plant is that fruit costs increase as the seed:ovule ratio decreases. However, because ovule abortion occurs earlier than does seed abortion, the former can reduce the biomass invested per seed (i.e., fruit costs) more efficiently than does the latter. Here, the frequencies of aborted ovules and seeds were analyzed in relation to the type of pollination treatment (open pollination vs. hand cross-pollination) and ovule/fruit position within pods of the leguminous shrub Caesalpinia gilliesii. The influence of ovule and seed abortion on fruit costs was analyzed by comparing the pericarp mass per seed between fruits with different frequencies of aborted ovules and seeds. The rate of ovule abortion was similar between hand cross-pollinated and open-pollinated fruits but was higher than that of seed abortion in one- and two-seeded fruits, as well as in those at stylar positions and in distal fruits. Hand cross-pollination reduced seed abortion but did not increase the seed:ovule ratio. In addition, fruits that aborted ovules were found to be less costly than were those that aborted seeds. From the mother plant perspective, these results indicate that ovule abortion is a more efficient mechanism of reducing fruit costs than is seed abortion, because fertilization opportunities decrease with position, and show that brood size is significantly influenced by the fate of the ovule at the pre-zygotic stage. <![CDATA[<b>Floristic composition and spatial distribution of vascular epiphytes in the <i>restingas</i> of Maracanã, Brazil</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100007&lng=pt&nrm=iso&tlng=pt Vascular epiphytes constitute a life form that is important to maintaining the biological diversity of forest ecosystems, because they provide food resources and specialized microenvironments for fauna in the forest canopy. This study aimed to describe the floristic composition and ecological aspects of vascular epiphytes occurring in the restingas (coastal woodlands) within the Algodoal-Maiandeua Environmentally Protected Area, located in the municipality of Maracanã, in the state of Pará, Brazil. We sampled five 50 × 50 m plots (three in dry restinga forest and two in floodplain restinga forest), the sampled area therefore totaling 1.25 ha. In the plots sampled, vascular epiphytes were identified and described according to their frequency, abundance, importance value (IV), functional group and vertical distribution (trunk, lower crown or upper crown of the host). For both forest types, we identified 477 individuals belonging to five families, nine genera and 11 species. The most species-rich families were Araceae and Orchidaceae. The species with the highest density, frequency and IV were the secondary hemiepiphytes Philodendron acutatum, Anthurium pentaphyllum and Philodendron muricatum, collectively accounting for 92.1% of all sampled individuals. The true epiphytes predominated. Epiphytic species richness and abundance was greater on the host trunk than in the lower or upper crown. The seasonal climate and structure of the forest favored greater abundance of secondary hemiepiphytes and a higher frequency of epiphytes on the trunks of their hosts. <![CDATA[<b>Seed rain in areas with and without bamboo dominance within an urban fragment of the Atlantic Forest</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100008&lng=pt&nrm=iso&tlng=pt Understanding the flow of diaspores is fundamental for determining plant population dynamics in a particular habitat, and a lack of seeds is a limiting factor in forest regeneration, especially in isolated forest fragments. Bamboo dominance affects forest structure and dynamics by suppressing or delaying the recruitment of and colonization by tree species as well as by inhibiting the survival and growth of adult trees. The goal of the present study was to determine whether dominance of the bamboo species Aulonemia aristulata (Döll) McClure in the forest understory influences species abundance and composition. We examined the seed rain at two noncontiguous sites (1.5 km apart) within an urban forest fragment, with and without bamboo dominance (BD+ and BD- areas, respectively). Sixty seed traps (0.5 m², with a 1-mm mesh) were set in the BD+ and BD- areas, and the seed rain was sampled from January to December 2007. Diaspores were classified according to dispersal syndrome, growth form and functional type of the species to which they belonged. There were significant differences between the two areas in terms of seed density, species diversity and dispersal syndrome. The BD+ area showed greater seed density and species diversity. In both areas, seed distribution was limited primarily by impaired dispersal. Bamboo dominance and low tree density resulted in fewer propagules in the seed rain. Our results suggest that low availability of seeds in the rain does not promote the maintenance of a degraded state, characterized by the presence of bamboo. <![CDATA[<b>Structure of the understory community in four stretches of <i>Araucaria</i> forest in the state of São Paulo, Brazil</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100009&lng=pt&nrm=iso&tlng=pt We analyzed the structure of the understory community in the Atlantic Forest sensu lato, for which phytosociological descriptions of the understory are lacking. We delineated 50 plots of 10 × 20 m each at four sites within an Araucaria forest (a subtype of Atlantic Forest), located in the municipalities of Bananal, Campos do Jordão, Itaberá and Barra do Chapéu, all of which are in the state of São Paulo, Brazil. To sample the resident species of the understory, we randomly selected five 1 × 1 m subplots within each plot, resulting in a total sampling area of 250 m² at each site. We identified differences among the locations, mostly due to proportional differences in growth forms, in terms of species richness and the importance values within the community. Factors potentially influencing the understory structure include macroclimatic and microclimatic conditions, as well as forest fragmentation, the abundance of deciduous trees in the canopy, the surrounding vegetation and geographic location. <![CDATA[<b>Characterization of Poaceae (grass) species as indicators of the level of degradation in a stretch of riparian forest in Matutina, Brazil</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100010&lng=pt&nrm=iso&tlng=pt Despite their extreme importance for environmental balance, riparian forests have been severely disturbed over time. This study aimed to identify grass species and determine their distribution in a disturbed stretch of riparian forest along Pimentas creek, in the municipality of Matutina, which is in the state of Minas Gerais, Brazil. Among four plots established within the study area, we recorded Pennisetum purpureum Schumach., Urochloa mutica (Forssk.) T.Q. Nguyen, Urochloa decumbens (Stapf) R.D. Webster, Paspalum notatum Flüggé and Andropogon bicornis L. The most common species was Pennisetum purpureum, which occurred in all of the plots, more frequently in those that had been disturbed. The proportions of exotic and native grasses, as well as their distribution, differed significantly among the plots. The distribution of the grass species varied according to the level of degradation of the creek bank, occurring more frequently where the bank had been disturbed. Therefore, we assume that grasses can be used as indicators of degradation in riparian zones. We also found that grasses are less efficient in preventing erosion than is the typical riparian vegetation. <![CDATA[<b>Myrtaceae throughout the Espinhaço Mountain Range of centraleastern Brazil</b>: <b>floristic relationships and geoclimatic controls</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100011&lng=pt&nrm=iso&tlng=pt Although biological surveys and taxonomic revisions provide key information to ecological and evolutionary studies, there is a clear lack of floristic and phytogeographic studies of the mountainous regions of Brazil, which harbor some of the most threatened plant ecosystems on the planet. Myrtaceae has been reported to be one of the most important families in the upland areas of Brazil, as well as in the Atlantic Forest Domain. In this study, we investigated the floristic composition of Myrtaceae throughout the Espinhaço Mountain Range and adjacent highlands of central-eastern Brazil, testing the following hypotheses: floristic similarity increases with geographic proximity; and species distribution is affected by geoclimatic variables. We performed statistical analyses using a database containing records of 199 species in 19 areas and of their respective geoclimatic variables. We also performed ordination analysis using non-metric multidimensional scaling (NMDS), the first and second axes of which explained 69% and 78% of the variation, respectively. The NMDS analysis demonstrated that variations in the Myrtaceae flora are highly sensitive to geoclimatic variables and geographic proximity. The NMDS ordination also showed a predominantly south-north gradient, as did the cluster analysis. This gradient was highly correlated with variations in rainfall and temperature, which are also associated with the three domains that coincide with the Espinhaço Mountain Range. <![CDATA[<b>Edge effect on vascular epiphytes in a subtropical Atlantic Forest</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100012&lng=pt&nrm=iso&tlng=pt Forest fragmentation affects biological communities by reducing habitat and increasing edges, thus reducing the effective size of the habitable zones. The subtropical atlantic Araucaria forest, typical on the southern Brazil, in some regions has been reduced to less than 1% of its original size lasting only in small isolated fragments. This study aimed to analyse the impact the edge has on vascular epiphyte ensemble in a remnant of Araucaria forest. We surveyed 40 host trees in four transects: one at the edge; and three at 15, 30 and 60 m from the edge. On each host tree we estimated the epiphyte biomass, using four size classes. We compared the transects using Jackknife estimator of absolute species number, diversity indices, non-metric multi-dimensional scaling and multi-response permutation procedure analysis. We recorded 85 epiphytes species. Absolute species richness and diversity were lower at the edge and higher at 60 m in from the edge. Shannon's evenness did not differ significantly among transects and Simpson's evenness values were inconsistent. The vascular epiphyte community under study was significantly altered by the edge. <![CDATA[<b>Coscinodiscophyceae and Fragilariophyceae (Diatomeae) in the Iguaçu River, Paraná, Brazil</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000100013&lng=pt&nrm=iso&tlng=pt A taxonomic survey was carried out on Coscinodiscophyceae and Fragilariophyceae found in the Iguaçu River catchment area within Iguaçu National Park, in the state of Paraná, Brazil. Between September 2007 and August 2008, we collected 24 samples from two stations on the Iguaçu River, upstream and downstream of the falls. We identified 37 taxa, including 22 specific and infraspecific taxa of Coscinodiscophyceae, together with 15 specific and infraspecific taxa of Fragilariophyceae. Melosira ruttneri Hustedt and Fragilaria alpestris Krasske ex Hustedt represent new records for Brazil.