We present the first well-resolved, taxon-rich phylogeny of the clusioid clade. Taxon sampling and resolution within the clade are greatly improved compared to previous studies and provide a strong basis for improving the classification of the group. In addition, our phylogeny will form the foundation for our future work investigating the biogeography of tropical angiosperms that exhibit Gondwanan distributions.

Aim\ud \ud We studied global variation in beta diversity patterns of lake macrophytes using regional data from across the world. Specifically, we examined (1) how beta diversity of aquatic macrophytes is partitioned between species turnover and nestedness within each study region, and (2) which environmental characteristics structure variation in these beta diversity components.\ud Location\ud \ud Global.\ud Methods\ud \ud We used presence–absence data for aquatic macrophytes from 21 regions distributed around the world. We calculated pairwise-site and multiple-site beta diversity among lakes within each region using Sørensen dissimilarity index and partitioned it into turnover and nestedness coefficients. Beta regression was used to correlate the diversity coefficients with regional environmental characteristics.\ud Results\ud \ud Aquatic macrophytes showed different levels of beta diversity within each of the 21 study regions, with species turnover typically accounting for the majority of beta diversity, especially in high-diversity regions. However, nestedness contributed 30–50% of total variation in macrophyte beta diversity in low-diversity regions. The most important environmental factor explaining the three beta diversity coefficients (total, species turnover and nestedness) was elevation range, followed by relative areal extent of freshwater, latitude and water alkalinity range.\ud Main conclusions\ud \ud Our findings show that global patterns in beta diversity of lake macrophytes are caused by species turnover rather than by nestedness. These patterns in beta diversity were driven by natural environmental heterogeneity, notably variability in elevation range (also related to temperature variation) among regions. In addition, a greater range in alkalinity within a region, likely amplified by human activities, was also correlated with increased macrophyte beta diversity. These findings suggest that efforts to conserve aquatic macrophyte diversity should primarily focus on regions with large numbers of lakes that exhibit broad environmental gradients

Recebido em 25/09/2001. Aceito em 01/06/2002RESUMO -(Hidrófitas fanerogâmicas de ecossistemas aquáticos temporários da planície costeira do Estado do Rio de Janeiro, Brasil). Foi realizado o levantamento florístico das hidrófitas fanerogâmicas de ambientes aquáticos temporários da planície costeira do norte fluminense. O material botânico foi coletado em 27 expedições entre setembro/1998 a julho/2001, herborizado e identificado segundo a metodologia tradicional. As exsicatas foram depositadas no Herbário da Universidade do Rio de Janeiro (HUNI). Foram encontrados 113 táxons, distribuídos em 40 famílias. Os ambientes estudados podem ser caracterizados floristicamente pela família Cyperaceae, representada por 23 táxons (cerca de 20%); seguida pelas famílias Fabaceae e Onagraceae (sete táxons), Poaceae (seis táxons), Asteraceae e Scrophulariaceae (cinco táxons) e Apiaceae, Lentibulariaceae e Polygonaceae (quatro táxons). Estes ambientes sofrem alterações fitofisionômicas marcantes relacionadas com a hidrogeologia. Algumas espécies são anuais, desaparecendo completamente na estiagem; outras suportam a seca, mas têm a população profundamente reduzida, alterando substancialmente a paisagem. Algumas espécies consideradas exclusivamente aquáticas foram encontradas em solo úmido, inclusive em floração. Isto demonstra a necessidade da inclusão de espécies anfíbias nos estudos da flora aquática pois, algumas vezes, a delimitação dos tipos biológicos não é muito definida, além de caracterizar de forma mais adequada estes ambientes.Palavras-chave -hidrófitas, florística, brejo temporário, Rio de Janeiro, planície costeira ABSTRACT -(Phanerogamic hydrophytes from the temporary swampy environments of coastal plains of northern Rio de Janeiro State, Brazil). A floristic inventory of phanerogamic hydrophytes from the temporary swampy environments of coastal plains of northern of Rio de Janeiro State was made. The botanical vouchers were collected in 27 expeditions between September/1998 and July/2001. They were herborized and identified by the traditional methodology. The exsicatae were deposited in the UNIRIO herbarium (HUNI). One hundred and thirteen taxa, distributed among 40 families were found. The environment analyzed could be floristically characterized by the Cyperaceae, represented by 23 taxa (ca. 20%), followed by Fabaceae and Onagraceae (seven taxa), Poaceae (six taxa), Asteraceae and Scrophulariaceae (five taxa) and Apiaceae, Lentibulariaceae and Polygonaceae (four

We studied community–environment relationships of lake macrophytes at two metacommunity scales using data from 16 regions across the world. More specifically, we examined (a) whether the lake macrophyte communities respond similar to key local environmental factors, major climate variables and lake spatial locations in each of the regions (i.e., within-region approach) and (b) how well can explained variability in the community–environment relationships across multiple lake macrophyte metacommunities be accounted for by elevation range, spatial extent, latitude, longitude, and age of the oldest lake within each metacommunity (i.e., across-region approach). In the within-region approach, we employed partial redundancy analyses together with variation partitioning to investigate the relative importance of local variables, climate variables, and spatial location on lake macrophytes among the study regions. In the across-region approach, we used adjusted R2 values of the variation partitioning to model the community–environment relationships across multiple metacommunities using linear regression and commonality analysis. We found that niche filtering related to local lake-level environmental conditions was the dominant force structuring macrophytes within metacommunities. However, our results also revealed that elevation range associated with climate (increasing temperature amplitude affecting macrophytes) and spatial location (likely due to dispersal limitation) was important for macrophytes based on the findings of the across-metacommunities analysis. These findings suggest that different determinants influence macrophyte metacommunities within different regions, thus showing context dependency. Moreover, our study emphasized that the use of a single metacommunity scale gives incomplete information on the environmental features explaining variation in macrophyte communities.Electronic supplementary materialThe online version of this article (10.1007/s00442-018-4294-0) contains supplementary material, which is available to authorized users.

Documenting the patterns of biological diversity on Earth has always been a central challenge in macroecology and biogeography. However, for the diverse group of freshwater plants, such research program is still in its infancy. Here, we examined global variation in taxonomic, functional and phylogenetic beta diversity patterns of lake macrophytes using regional data from six continents. A data set of ca. 480 lake macrophyte community observations, together with climatic, geographical and environmental variables, was compiled across 16 regions worldwide. We (a) built the very first phylogeny comprising most freshwater plant lineages; (b) exploited a wide array of functional traits that are important to macrophyte autoecology or that relate to lake ecosystem functioning; (c) assessed if different large-scale beta diversity patterns show a clear latitudinal gradient from the equator to the poles using null models; and (d) employed evolutionary and regression models to first identify the degree to which the studied functional traits show a phylogenetic signal, and then to estimate community-environment relationships at multiple spatial scales. Our results supported the notion that ecological niches evolved independently of phylogeny in macrophyte lineages worldwide. We also showed that taxonomic and phylogenetic beta diversity followed the typical global trend with higher diversity in the tropics. In addition, we were able to confirm that species, multi-trait and lineage compositions were first and foremost structured by climatic conditions at relatively broad spatial scales. Perhaps more importantly, we showed that large-scale processes along latitudinal and elevational gradients have left a strong footprint in the current diversity patterns and community-environment relationships in lake macrophytes. Overall, our results stress the need for an inte-grative approach to macroecology, biogeography and conservation biology, combining multiple diversity facets at different spatial scales.

Descripción de la familia por A. Novelo R., C.T. Philbrick y G.E. Crow.Annual or perennial herbs, firmly attached to rocks and other solid substrata of waterfalls and rivers and streams with seasonally strong current. Roots linear, prostrate and flattened, green, branched or not. Stems arising along the flanks of roots, opposite or sub-opposite, disk-shaped (holdfast-like) or upright, attached firmly to the substratum. Leaves distichous or tristichous, clustered and rosette-like or projecting from an upright stem, petiolate or sessile; petioles terete to flattened, sometimes winged, mono-or dithecous; blades variable, simple, lobed, repeatedly pinnately or dichotomously compound or ensiform, when divided, the ultimate divisions hairlike or flattened, blunt or acute at the apex. Flowers solitary or fascicled, pedunculate or not, actinomorphic or zygomorphic, enclosed in bud by a sac-like spathella or a spathella lacking; tepals 3-9, scale-like, free or fused basally, linear or triangular; stamens 2-11, free or fused basally, in a complete whorl , or confined to one side of flower, the filaments elongating during anthesis, the anthers basifixed, dehiscing introrsely or latrorsely; pollen in monads or dyads; ovary 2-3-locular, superior, the placenta fleshy; stigmas 2-3, apically free or fused basally. Capsules 2-3-locular, 2-3-valved, longitudinally ribed, both valves persistent or one deciduous, the suture margins often thickened or not; seeds tiny, numerous, becoming sticky upon wetting. 47 gen., approx. 270 spp. Pantropical, a few species extending into temperate eastern Asia and eastern North America.Plants grow attached tightly to rocks or other solid substrata in strong currents of riverrapids and waterfall habitats. Flowering and seed production occurs when plants become exposed during seasonally low water levels.Bibliografía [matted]. Leaves scale-like, arranged in ramuli, generally tristichous, sessile, membranous, nerveless or 1-nerved. Flowers solitary, bisexual, enclosed by 2 bracts in bud; pedicellate; tepals 3, persistent, usually united at the base; stamens 1(2), the filaments slender, the anthers basifixed, dehiscing introrsely or latrorsely; pollen in monads; ovary 3-locular; stigmas 3, free, cylindrical; ovules numerous, the placenta axile. Capsules with 3 equal valves, persistent, each valve 3-ribbed, the suture margins not thickened and rib-like; seeds numerous, dust-like. Perennials. Roots 0.3-1.2 mm wide, prostrate, linear. Stems 1-11 cm, ascending to procumbent, branched or simple. Leaves 0.6-7 × 0.4-0.9 mm, 3-ranked (tristichous), scale-like, the apex acute to rounded. Pedicels 0.15-1.5 cm; lowest floral bract at pedicel base 1.1-2.8 mm, the adjacent upper bract 1-2.6 mm. Tepals 3-lobed, 1.3-2 mm, united at the base; stamens 1(2), the filaments 0.8-1.9 mm, the anthers 0.3-0.9 mm; stigmas 0.2-0.7 mm. Capsules 1-2 × 0.7-1. Tristicha trifaria is the most common member of the family in the Americas, and appears to be fairly tolerant of stream pollution. Its moss-like appearance, however, contri...

Descripción de la familia por A. Novelo R., C.T. Philbrick y G.E. Crow.Annual or perennial herbs, firmly attached to rocks and other solid substrata of waterfalls and rivers and streams with seasonally strong current. Roots linear, prostrate and flattened, green, branched or not. Stems arising along the flanks of roots, opposite or sub-opposite, disk-shaped (holdfast-like) or upright, attached firmly to the substratum. Leaves distichous or tristichous, clustered and rosette-like or projecting from an upright stem, petiolate or sessile; petioles terete to flattened, sometimes winged, mono-or dithecous; blades variable, simple, lobed, repeatedly pinnately or dichotomously compound or ensiform, when divided, the ultimate divisions hairlike or flattened, blunt or acute at the apex. Flowers solitary or fascicled, pedunculate or not, actinomorphic or zygomorphic, enclosed in bud by a sac-like spathella or a spathella lacking; tepals 3-9, scale-like, free or fused basally, linear or triangular; stamens 2-11, free or fused basally, in a complete whorl , or confined to one side of flower, the filaments elongating during anthesis, the anthers basifixed, dehiscing introrsely or latrorsely; pollen in monads or dyads; ovary 2-3-locular, superior, the placenta fleshy; stigmas 2-3, apically free or fused basally. Capsules 2-3-locular, 2-3-valved, longitudinally ribed, both valves persistent or one deciduous, the suture margins often thickened or not; seeds tiny, numerous, becoming sticky upon wetting. 47 gen., approx. 270 spp. Pantropical, a few species extending into temperate eastern Asia and eastern North America.Plants grow attached tightly to rocks or other solid substrata in strong currents of riverrapids and waterfall habitats. Flowering and seed production occurs when plants become exposed during seasonally low water levels.Bibliografía [matted]. Leaves scale-like, arranged in ramuli, generally tristichous, sessile, membranous, nerveless or 1-nerved. Flowers solitary, bisexual, enclosed by 2 bracts in bud; pedicellate; tepals 3, persistent, usually united at the base; stamens 1(2), the filaments slender, the anthers basifixed, dehiscing introrsely or latrorsely; pollen in monads; ovary 3-locular; stigmas 3, free, cylindrical; ovules numerous, the placenta axile. Capsules with 3 equal valves, persistent, each valve 3-ribbed, the suture margins not thickened and rib-like; seeds numerous, dust-like. Perennials. Roots 0.3-1.2 mm wide, prostrate, linear. Stems 1-11 cm, ascending to procumbent, branched or simple. Leaves 0.6-7 × 0.4-0.9 mm, 3-ranked (tristichous), scale-like, the apex acute to rounded. Pedicels 0.15-1.5 cm; lowest floral bract at pedicel base 1.1-2.8 mm, the adjacent upper bract 1-2.6 mm. Tepals 3-lobed, 1.3-2 mm, united at the base; stamens 1(2), the filaments 0.8-1.9 mm, the anthers 0.3-0.9 mm; stigmas 0.2-0.7 mm. Capsules 1-2 × 0.7-1. Tristicha trifaria is the most common member of the family in the Americas, and appears to be fairly tolerant of stream pollution. Its moss-like appearance, however, contri...

With the advent of next-generation sequencing technologies, whole-plastome data can be obtained as a byproduct of low-coverage sequencing of the plant genomic DNA. This provides an opportunity to study plastid evolution across groups, as well as testing phylogenetic relationships among taxa. Within the order Malpighiales (∼16,000 spp.), the Podostemaceae (∼300 spp.) stand out for their unique habit, living attached to rocks in fast-flowing aquatic habitats, and displaying highly modified morphologies that confound our understanding of their classification, biology, and evolution. In this study, we used genome skimming data to assemble the full plastid genome of 5 species within Podostemaceae. We analyzed our data in a comparative framework within Malpighiales to determine the structure, gene content, and rearrangements in the plastomes of the family. The Podostemaceae have one of the smallest plastid genomes reported so far for the Malpighiales, possibly due to variation in length of inverted repeat (IR) regions, gene loss, and intergenic region variation. We also detected a major inversion in the large single-copy region unique to the family. The uncommon loss or pseudogenization of ycf1 and ycf2 in angiosperms and in land plants in general is also found to be characteristic of Podostemaceae, but the compensatory mechanisms and implications of this and of the pseudogenization of accD , rpl22 , and clpP and loss of rps16 remain to be explained in this group. In addition, we estimated a phylogenetic tree among selected species in Malpighiales. Our findings indicate that the Podostemaceae are a distinct lineage with long branches that suggest faster rates of evolution in the plastome of the group, compared with other taxa in the order. This study lays the foundations for future phylogenomic studies in the family.