Spirotropis (Leguminosae, Papilionoideae) is a Neotropical genus of trees that has long remained circumscribed to just one species, S. longifolia . Evidence from previous molecular phylogenetic analyses of nuclear and plastid loci and morphological features supports expanding its circumscription to encompass species from the polyphyletic Clathrotropis s.l. that are widely distributed in the Amazonian forests. Here, we reassess the evolutionary relationships of Spirotropis and Clathrotropis s.l. based on a new plastome‐wide phylogenomic analysis of the genistoid legumes. The evolutionary histories of selected morphological characters were estimated through Bayesian stochastic mapping over a robust phylogeny of the Ormosieae clade in order to investigate synapomorphies that define an expanded concept of Spirotropis . The newly circumscribed genus Spirotropis was recovered as a well‐supported monophyletic group comprising five species: the type S. longifolia , three species added from Clathrotropis s.str. ( S. nitida , S. paradoxa , S. rosea ) and the newly described S. fusca endemic to Venezuela. These species are represented by trees with fragrant flowers and spirally twisted keel petals that grow from tropical lowland rain forests, including seasonally flooded forests, to montane forests. In this study, we present identification keys for the Ormosieae genera and the Spirotropis species, in addition to full taxonomic descriptions, illustrations, maps of geographic distribution, and comments on the morphological distinctiveness, nomenclature, and ecology of each species.

A new species of Swartzia section Terminales—S. neglecta—is described from the threatened Chocó-Darién biodiversity hotspot of western Colombia. Distinction of the species from close relatives is based on morphological diagnosability and geographical range cohesion, as revealed by analysis of data obtained from herbarium specimens. Swartzia neglecta is distinctive in bearing prominent villous to lanate indumentum on the filaments of the two larger stamens, among other features. It is also notable for the time elapsed between its first collection in 1857 and its publication in this work. A preliminary conservation status assessment employing the IUCN Red List threat categories and criteria suggests that S. neglectashould be categorized as Near Threatened.

Eriocaulaceae is a pantropical family of approximately 1200 species across 18 genera, with its highest diversity in the Neotropical region. Traditionally, the family has been divided into two subfamilies, Eriocauloideae and Paepalanthoideae, based on floral traits. Here, we use target-capture sequencing of nuclear markers to test the monophyly of these subfamilies. Using the Angiosperms353 probe set, we analyzed data from 30 species, generating new sequences for 24 species, representing eight genera of Eriocaulaceae. Phylogenetic analyses using ASTRAL-III and a concatenated maximum likelihood approach recovered three major clades, revealing that Paepalanthoideae is non-monophyletic. Monosperma, a Pantepui-endemic lineage, recently elevated to generic status, emerged as the sister group to the rest of the family. Our findings suggest that the ancestral Eriocaulaceae flower had a single-whorled androecium, contrary to previous hypotheses. Additionally, this study highlights the non-monophyletic nature of the broad circumscription of Paepalanthus. These results challenge long-held assumptions about the evolutionary relationships within Eriocaulaceae, providing critical insight into its subfamilial and generic classification, and call for further research into the evolutionary history of the family.

Rhynchosia Lour. has a pantropical distribution and comprises approximately 230 species, of which ca. 55 occur in the Neotropics and 31 in South America. The only existing taxonomic review that treated the South American species of the genus was carried out in 1978. It does not account for many new collections and several recently described species, and the delimitation of taxa remains problematic. Consequently, we undertook a comprehensive review of the South American species of Rhynchosia and present here a new taxonomic revision. The revision is based on our own fieldwork, extensive study of the relevant literature, and analysis of ca. 2000 herbarium collections including the nomenclatural types for all published names that have been linked to the South American taxa of Rhynchosia. Twenty-seven species are recorded for South America, where they are distributed in a variety of open and forested habitats, with the greatest diversity concentrated in the Cerrado domain. Most of the South American taxa are widely distributed in this region and some also occur in Central and North America. Rhynchosia minima is the only species in South America with a larger distribution that extends to the Old World. We provide an identification key, morphological descriptions for all of the recorded taxa, information about the nomenclatural types, synonyms, geographical distributions, habitats, phenology, and conservation status, as well as distribution maps, illustrations and photos of selected species in the field. We present six new synonymizations and 50 lectotypifications, of which 30 are second-step.

Molecular phylogenetic studies focused on the early-branching papilionoid legumes have revealed many new clades and supported several generic realignments, yet the monophyly of some of the constituent genera has remained unassessed. This is the case for the Amazonian genus Clathrotropis of the tribe Ormosieae. The genus, as traditionally circumscribed, comprises seven species of trees, including some of the most ecologically hyper dominant taxa across the Amazonian terra firme and seasonally flooded forests. Here we employed a Bayesian analysis of densely sampled nuclear ribosomal ITS/5.8S and plastid matK and trnL intron DNA sequences to evaluate the monophyly of Clathrotropis. All individual and concatenated analyses concurred in showing the non-monophyletic nature of Clathrotropis, whose species fall into three distantly related lineages: one, comprised of C. brachypetala, C. brunnea, C. glaucophylla and the ecologically dominant C. macrocarpa, is circumscribed here as the new genus Cabari; the two others, comprising C. paradoxa and the widespread C. nitida, are more closely related to Spirotropis of the tribe Ormosieae. Such phylogeny-based dismemberment of Clathrotropis is further supported by vegetative, floral, fruit, and seed characters. Although the genes analysed in this study have provided phylogenetically informative data supporting the need for a new circumscription of Clathrotropis, we suggest that future phylogenomic studies should seek to better resolve the relationships of the newly described genus Cabari across the phylogenetically recalcitrant early-branching nodes of the Genistoid clade.

Bonnetia is the most representative genus of the Pantepui woody flora and is among the groups with the greatest endemism in the local flora. The genus has 28 currently recognized species in tropical America, 26 of them endemic to the Pantepui. Here we describe Bonnetia ayangannensis from the summit of Mount Ayanganna tepui in Guyana, providing a morphological description, illustrations, distribution maps, characterization of micromorphology under scanning electron microscopy and leaf venation, comments comparing the new species with closely related species, and a key for the identification of the species of Bonnetia occurring in Guyana. With its restricted distribution threatened by climate change, Bonnetia ayangannensis is assessed in the conservation threat category of Critically Endangered. Its description raises the number of endemic species of Bonnetia in the Pantepui to 27.

Stylosanthes Sw. is a pantropical genus primarily distributed throughout the Americas, with the Brazilian Cerrado serving as its principal center of diversity. Many of its species hold significant economic potential and are widely utilized as fodder for cattle. Systematic examinations involving both morphology and nomenclature have highlighted the imperative need for taxonomic updates in select species. Given the observed morphological and ecological differences, a taxonomic reevaluation of S. guianensis (Aubl.) Sw. was deemed necessary, leading to the elevation of its varieties to the species level. The taxonomic changes include the new combinations S. microcephala (M.B. Ferreira & Sousa Costa) Gissi, S. pauciflora (M.B. Ferreira & Sousa Costa) Gissi, and S. pubescens (Pilger) Gissi. Furthermore, a neotype for S. nunoi Brandão is designated due to the loss of the holotype. Stylosanthes pohliana Taub. is reinstated as an accepted species, and a novel species within the genus is described. X-ray imaging of leaflets emerges as a valuable tool for taxonomic discrimination. This comprehensive study not only presents nomenclatural modifications but also provides illustrations, comments on diagnostic characteristics, distribution maps, and preliminary IUCN conservation assessments. Additionally, a novel discovery is introduced with the recognition of an elaiosome in the fruits of S. guianensis , constituting a noteworthy addition to the tribe Dalbergieae.

A new species of Stylosanthes (Leguminosae – Papilionoideae) from the Chapada das Mesas National Park in Maranhão, Brazil, is described. The new species, S. acicularis, was misidentified as S. angustifolia in the SLUI herbarium. It differs from S. angustifolia especially by inflorescence shape and rostrum length. The new species closely resembles S. hippocampoides by its small capitate inflorescences, absence of a rudimentary axis beneath the flower, only one inner bracteole, loments with only one fertile article and a very short rostrum, and the absence of a marginal vein and possession of up to five secondary veins in the leaflets. However, the two species differ by stem indumentum, bristle length, leaflet shape and venation, and shape of the outer bracteole margin. A morphological description, illustrations—including X-ray imaging of the leaflet venation—and notes on the geographical distribution, habitat, and conservation status of the new species are presented.

Alexa (Leguminosae, Papilionoideae) comprises nine species of Amazonian trees. An updated analysis of morphological variation in the genus indicated that material identified as Alexa grandiflora in herbaria constituted two distinct species, one of which appeared to be new. Subsequent fieldwork further supported the distinction. Here, we describe the new species, Alexa duckeana, which differs from A. grandiflora, most notably by lacking extrafloral glands and by having shorter pedicels and shorter racemes with more congested flowers. Alexa duckeana occurs only in the southeastern region of Pará, in northern Brazil. We assess its conservation status as Endangered. In addition to the description, we provide an illustration and distribution map for the new species, taxonomic comparisons, and an identification key for the species of Alexa that occur in Brazil.

Aim: Functional traits shape the distribution of taxa across environments. However, it remains unclear whether trait and environmental niche evolution are correlated, and what happened first: trait change facilitating environment shifts (pre-adaptation) or environmental change leading to trait change (adaptation). We focus on a species-rich

Martiodendron (Leguminosae/Fabaceae) is a Neotropical genus of trees and shrubs comprising five species. It is characterized by its yellow pentamerous corolla, four to five long poricidal anthers and large, attractive red samaras; it represents an intermediate stage of floral reduction among the 17 genera of the subfamily Dialioideae, which display diverse floral morphologies including different types of reduced flowers in the perianth and androecium. The last taxonomic revision of Martiodendron was published some 60 years ago and there is frequent misidentification of specimens in herbaria, databases, and floristic works with mistreatment of taxa and unclear geographic distributions. Thus, circumscriptions of the species and varieties of the genus require reassessment in light of the substantial new data that has become available during the last several decades. Here, we synthesized morphological, geographical, and ecological data on the genus to produce a modern integrative taxonomic treatment. Our taxonomic concepts are underpinned by analysis of 352 herbarium specimens and substantial fieldwork in South America. We recognize five species and four varieties of Martiodendron. All of these taxa display high levels of morphological and geographical cohesion. One of the varieties, M. mediterraneum var. concinnum, is described as new to science. Detailed descriptions of each recognized taxa are accompanied by illustrations, distribution maps, conservation status assessments, and complete nomenclatural treatments with four new lectotypifications. An identification key and a morphometric analysis of fruits are also provided.

Dicorynia stands out among the 17 genera of the diverse legume subfamily Dialioideae as an example of extreme floral reduction and specialization. It has asymmetric flowers presenting a heteromorphic calyx, trimerous corolla, and pair of highly dimorphic stamens, with one or both anthers polysporangiate. The two species of Dicorynia are Amazonian trees, one of which is highly valued for its timber. Despite the economic importance of the genus and an abundance of new collections, no comprehensive taxonomic study of Dicorynia has been completed since the publication of Koeppen’s monograph almost six decades ago, in which two species were recognized, one of which divided into six varieties. The present work employs integrative analysis of geographical, ecological, and extensive specimen-based morphological data to test previous delimitations of species and varieties. A new classification is adopted in an updated and comprehensive taxonomic revision of Dicorynia. We maintain two morphologically distinct and geographically separated species, D. guianensis and D. paraensis. The former is restricted to portions of the Guiana Shield north of the Amazon basin. At the same time, the latter is broadly distributed in the Amazon basin, but mainly north of the Amazon River. We recognize several taxonomically significant entities within the latter species, which, because they display limited morphological overlap and substantial geographical sympatry, we treat as varieties. However, we reduce the number of varieties from six to four. The taxonomic treatment contains new descriptions and illustrations, distribution maps, including two new areas of occurrence, conservation status assessments for all treated taxa, and identification keys to distinguish them. Nomenclatural, biogeographical, and ecological comments, including two new lectotypifications, are provided.

Stylosanthes comprises about 50 species, with Brazil being one of the main diversity centers. Stylosanthes guianensis constitutes a problematic taxonomic complex, comprising four varieties of S. guianensis and seven other species. Considering the difficulty of taxon delimitation, this study assessed the potential value of the secretory structures and other anatomical characters to the diagnosis of taxa within the complex. We analyzed the leaflet and stem anatomy and micromorphology of representatives of the S. guianensis complex using light and scanning electron microscopy. Long uniseriate non-glandular hairs occurred on the stems and leaflets of all species. Secretory emergences with a dilated base and a tapered distal portion occurred on both stems and leaflets, except in S. guianensis var. canescens. Polysaccharides, lipids and terpenes were histochemically detected in the secretory exudates. In the stem of S. gracilis, chlorenchyma cells were observed to be radially elongated, while in the other taxa studied they were isodiametric. On leaflets of S. guianensis var. pauciflora, S. acuminata, S. aurea, and S. gracilis, the midrib was eccentric and the veins closer to the leaflet margin had larger fiber caps. Anatomical structures proved to be useful for separating taxa. Stylosanthes guianensis var. canescens and S. guianensis var. pauciflora differ from the other varieties of the species and are possibly worthy of recognition at species rank. Our findings also reinforce the status of S. gracilis as a distinct species.

We present the most complete molecular phylogeny to date of the Pithecellobium clade of subfamily Caesalpinioideae. This neotropical group was informally recognised (as the Pithecellobium alliance) at the end of the 20th century by Barneby and Grimes (1996) and includes five genera and 33 species distributed from the southern United States and Caribbean Islands to north-eastern South America. Our aims were to further test the monophyly of the group and its genera and to identify sister group relationships within and amongst the genera. A phylogenetic analysis of nuclear ribosomal DNA sequences (ITS and ETS) was performed. The results provide further support for the monophyly of the Pithecellobium clade. The genera Ebenopsis, Pithecellobium and Sphinga were strongly supported as monophyletic. Havardia and Painteria were found to be non-monophyletic, prompting their re-circumscriptions and the description of two new genera: Gretheria and Ricoa. New combinations are made for the three species transferred to the new genera.

The papilionoid legume genus Ormosia (Fabaceae) comprises about 150 species of trees and exhibits a striking disjunct geographical distribution between the New World-and Asian and Australasian wet tropics and subtropics. Modern classifications of Ormosia are not grounded on a well-substantiated phylogenetic hypothesis and have been limited to just portions of the geographical range of the genus. The lack of an evolutionarily-based foundation for systematic studies has hindered taxonomic work on the genus and prevented the testing of biogeographical hypotheses related to the origin of the Old World/New World disjunction and the individual dispersal histories within both areas. Here, we present the most comprehensively sampled molecular phylogeny of Ormosia to date, based on analysis of both nuclear (ITS) and plastid (matK and trnL-F) DNA sequences from 82 species of the genus. Phylogenetically-based divergence times and ancestral range estimations are employed to test hypotheses related to the biogeographical history of the genus. We find strong support for the monophyly of Ormosia and the grouping of all sampled Asian species of the genus into two comparably sized clades, one of which is sister to another large clade containing all sampled New World species. Within the New World clade, additional resolution supports the grouping of most species into three mutually exclusive subordinate clades. The remaining New World species form a fourth well-supported clade in the analyses of plastid sequences, but that result is contradicted by the analysis of ITS. With few exceptions the supported clades have not been previously recognized as taxonomic groups. The biogeographical analysis suggests that Ormosia originated in continental Asia and dispersed to the New World in the Oligocene or early Miocene via long-distance trans-oceanic dispersal. We reject the hypothesis that the inter-hemispheric disjunction in Ormosia resulted from fragmentation of a more continuous "Boreotropical" distribution since the dispersal post-dates Eocene climatic maxima. Both of the Old World clades appear to have originated in mainland Asia and subsequently dispersed into the Malay Archipelago and beyond, at least two lineages dispersing across Wallace's Line as far as the Solomon Islands and northeastern Australia. In the New World, the major clades all originated in Amazonia. Dispersal from Amazonia into peripheral areas in Central America, the Caribbean, and Extra-Amazonian Brazil occurred multiple times over varying time scales, the earliest beginning in the late Miocene. In a few cases, these dispersals were followed by local diversification, but not by reverse migration back to Amazonia. Within each of the two main areas of distribution, multiple modest bouts of oceanic dispersal were required to achieve the modern distributions.

Ferns and lycophytes are an excellent group for conservation and species distribution studies because they are closely related to environmental changes. In this study, we analyzed collection gaps, sampling biases, richness distribution, and the species conservation effectiveness of protected areas in the Lower Tapajós River Basin using ferns and lycophytes as a model group. We built a database based on herbarium specimens that were taxonomically verified and georeferenced. We then examined the relationship between sampling effort and documented species richness and tested for collection bias towards access routes (navigable rivers and roads). We made a comparison of species composition among the study areas and sixteen other areas in the Brazilian Amazon using non-metric multidimensional scaling (NMDS) and tested whether floristic similarity was correlated with geographic distance. We found that more than 92% of the area is unsampled and that collecting effort is highly biased towards areas along access routes, such as roads and navigable rivers. Only four out of the seven protected areas in the Lower Tapajós Basin had records of ferns and lycophytes. We present here species checklists for those areas. In total, we recorded 151 species of 60 genera and 24 families. Five species are new records for the state of Pará, and nine out of the 151 species recorded occur only outside protected areas. Species composition is most similar among areas sharing similar vegetation types; geographic closeness does not necessarily reflect floristic similarity. We conclude that the fern and lycophyte flora the Brazilian Amazon is still far from complete and recommend the direction of future collection efforts to other under-sampled portions of the region. Such a sampling strategy will reduce sampling bias and providing a better knowledge base for the conservation of Amazonian fern and lycophyte diversity.

Abstract— Strychnos is a pantropical genus of Loganiaceae (Gentianales), with approximately 200 species, that lacks a detailed worldwide phylogenetic understanding until now. We investigated the global phylogeny of the majority of Strychnos species, and evaluated morphological and key character patterns to discuss congruence between phylogenetic clades and sectional classification systems. We included 147 ITS sequences across 12 genera, with 127 samples (103 species) of Strychnos and 20 outgroup accessions (19 species) in a Bayesian analysis. Tribes Antonieae, Loganieae, and Spigelieae were supported as monophyletic, but Strychneae was resolved as polyphyletic due to the positioning of Gardneria placed outside of the Strychnos + Neuburgia clade. Strychnos was supported as strongly monophyletic with 12 strongly supported clades, but the relationships among many of these clades were not well resolved. Most of the 12 sections in the current infrageneric classification system of Strychnos were resolved as non-monophyletic, indicating the need for a revision of the sectional divisions. Characters common in species placed within the relatively more nested clades include a non-climbing habit, invasion of non-rainforest habitats, absence of tendrils, absence of secondary phloem, and elongated corolla tubes, suggesting that these characters are relatively derived conditions in the genus. Inflorescence position, fruit size, and fruit wall thickness are extremely variable and were distributed among various clades in our phylogeny. Stamen, pistil, seed and seed coat, and phytochemical characters have figured prominently in the taxonomy of the genus, but are as yet incompletely described, thus preventing significant inference about their evolution. Most of the 12 well-supported clades within Strychnos are restricted to specific continents, sometimes with limited dispersion between neighboring continents, suggesting a history of repeated cross-oceanic dispersal or vicariance patterns. The Neotropical clades nested within the African clades have the shortest branches and the most unresolved topologies, probably indicating relatively recent radiation in the Neotropics.

A taxonomic treatment, based on herbarium study and field observations, is presented for the Brazilian species of Myriocladus (Poaceae, tribe Bambuseae, subtribe Arthrostylidiinae), a genus of woody bamboos restricted to geographically isolated uplands of the Pantepui region of Brazil, Venezuela, and Guyana. Of the 12 accepted species of Myriocladus, five are recorded from Brazil, of which four also occur in Venezuela. One species, M. caburaiensis, is known from a single collection from Brazilian territory near the frontier with Guyana and is described herein for the first time. We also provide a key to distinguish the five Brazilian species and illustrations of each.