The generic classification of the Thelypteridaceae has been the subject of much controversy. Proposed taxonomic systems have varied from recognizing the approximately 1200 species in the family within the single genus Thelypteris, to systems favoring upwards of 30 genera. Insights on intrafamilial relationships, especially for neotropical taxa, have been gained from recent phylogenetic studies; however, in the most recent classification, 10 of 30 recognized genera are either non-monophyletic or untested. We sequenced 407 nuclear loci for 621 samples, representing all recognized genera and approximately half the known species diversity. These were analyzed using both maximum likelihood analysis of a concatenated matrix and multi-species coalescent methods. Our phylogenomic results, informed by recently published morphological evidence, provide the foundation for a generic classification which recircumscribed 14 genera and recognized seven new genera. The 37 monophyletic genera sampled demonstrate greater geographic coherence than previous taxonomic concepts suggested. Additionally, our results demonstrate that certain morphological characters, such as frond division, are evolutionarily labile and are thus inadequate for defining genera.

Cyclodium is a neotropical fern genus with 13 species, most of them distributed in the Amazonian lowlands, particularly in the Guianan region and along the border with the Andes. It belongs to the polybotryoid clade of Dryopteridaceae, being unique within this clade by a combination of characters related to rhizome growth, leaf dimorphism, anastomosing venation, and peltate indusia. Here we present a molecular phylogenetic hypothesis for Cyclodium resulting from Bayesian and maximum likelihood analyses, using molecular sequences of five plastid markers. We also map 12 morphological characters and habit onto the resulting trees. Our results support Cyclodium as monophyletic and sister to Polybotrya. The presence of peltate indusia is the main character distinguishing Cyclodium. Our results also suggest that plesiomorphic conditions in Cyclodium are free venation (vs. anastomosing), creeping rhizomes (vs. erect or decumbent), highly dissected laminae (vs. 1-pinnate), monomorphic sterile and fertile fronds (vs. dimorphic), and pinnatifid apices (vs. conform).

A recent phylogenetic tree for the large paraphyletic genus Paepalanthus showed that the genus Actinocephalus is also paraphyletic with two species of Paepalanthus nested within it: Paepalanthus macrocephalus and Paepalanthus camptophyllus. These species have the diagnostic morphological traits of Actinocephalus, but they are too small to be seen in Paepalanthus macrocephalus and difficult to interpret in Paepalanthus camptophyllus, which has resulted in them being overlooked until now. Furthermore, Paepalanthus macrocephalus has a challenging circumscription, with several putative synonyms whose nomenclatural confusion has persisted for decades. Here we analyzed the morphology of Paepalanthus camptophyllus and Paepalanthus macrocephalus to confirm their relationship with other species of Actinocephalus as shown in the phylogeny and to investigate the diagnostic features that distinguish these species in Actinocephalus. The opportunity was also taken to evaluate putative synonyms of Paepalanthus macrocephalus and Paepalanthus camptophyllus, and to include the remaining variety of A. phaeocephalus (Paepalanthus phaeocephalus var. foliosus) in Actinocephalus, which was lacking in the revision of the genus. Four new combinations and eight lectotypes are provided, as well as six new synonyms. We also provide comments on diagnostic characteristics, distribution, and notes on Actinocephalus.

The genus Eleocharis (Cyperaceae, monocotyledons) is characterized by bladeless leaves, which are leaves having only leaf-sheaths. To study the evolutionary process through which Eleocharis species lost their leaf blades, we analyzed the outer morphological and anatomical characters of the representative Eleocharis species, plus species from nine phylogenetically related genera. From the analysis, we recognized eight characters and we optimized their character states on a recent molecular phylogenetic tree. As a result, we recognized five characteristics shared by Eleocharis species as follows: (1) the most apical internode is more than seven times longer than the next apical internode; (2) bladeless leaves having only leaf sheaths; (3) transversely septate aerenchyma in culms; (4) densely and peripherally located, slender, and square timber-shaped fiber bundles in culms; and (5) palisade chlorenchyma in culms. In these characteristics, (2) and (4) are synapomorphies of Eleocharis. These two apomorphic characteristics seemed to be adaptations for inhabiting running waters.

Little is known about the effects of habitat fragmentation on the patterns of genetic diversity and genetic connectivity of species in the remaining tropical forests of Southeast Asia. This is particularly evident in Cebu, a Philippine island that has a long history of deforestation and has lost nearly all of its forest cover. To begin filling this gap, data from 13 microsatellite loci developed for Tetrastigma loheri (Vitaceae), a common vine species in Philippine forests, were used to study patterns of genetic diversity and genetic connectivity for the four largest of the remaining forest areas in Cebu. Evidence of relatively high levels of inbreeding was found in all four areas, despite no evidence of low genetic diversity. The four areas are genetically differentiated, suggesting low genetic connectivity. The presence of inbreeding and low genetic connectivity in a commonly encountered species such as T. loheri in Cebu suggests that the impact of habitat fragmentation is likely greater on rare plant species with more restricted distributions in Cebu. Conservation recommendations for the remaining forest areas in Cebu include the establishment of steppingstone corridors between nearby areas to improve the movement of pollinators and seed dispersers among them.

Plants from Brazilian campos rupestres usually present morphological strategies that allow them to survive in extreme environments. However, in Chamaecrista (Leguminosae, Caesalpinioideae), one of the most diverse genera in the campos rupestres, needle-like leaflets are rare. Reviewing the species that present such leaf morphology, we describe Chamaecrista acicularis, a new species from the Canastra Range, in the southwestern region of the state of Minas Gerais, Brazil. Phylogenetic analyses revealed that C. acicularis is not closely related to other quite similar needle-like leafleted species and that this trait evolved convergently. We also present comments on the phylogenetic relationships of needle-like leafleted species as well as the evolution of the leaflet amplitude, and a detailed description of C. acicularis alongside illustrations, photos, geographical distribution, a key to the needle-like leafleted species and taxonomic notes on similar species. Additionally, we expand the description of Chamaecrista strictifolia and present an informal conservation status for all needle-like leafleted species.

The genus Castanea in North America contains several tree and shrub taxa of conservation concern. The two species within the group, American chestnut (Castanea dentata) and chinquapin (C. pumila sensu lato), display remarkable morphological diversity across their distributions in the eastern United States and southern Ontario. Previous investigators have hypothesized that hybridization between C. dentata and C. pumila has played an important role in generating morphological variation in wild populations. A putative hybrid taxon, Castanea alabamensis, was identified in northern Alabama in the early 20th century; however, the question of its hybridity has been unresolved. We tested the hypothesized hybrid origin of C. alabamensis using genome-wide sequence-based genotyping of C. alabamensis, all currently recognized North American Castanea taxa, and two Asian Castanea species at > 100,000 single-nucleotide polymorphism (SNP) loci. With these data, we generated a high-resolution phylogeny, tested for admixture among taxa, and analyzed population genetic structure of the study taxa. Bayesian clustering and principal components analysis provided no evidence of admixture between C. dentata and C. pumila in C. alabamensis genomes. Phylogenetic analysis of genome-wide SNP data indicated that C. alabamensis forms a distinct group within C. pumila sensu lato. Our results are consistent with the model of a nonhybrid origin for C. alabamensis. Our finding of C. alabamensis as a genetically and morphologically distinct group within the North American chinquapin complex provides further impetus for the study and conservation of the North American Castanea species.

The morphology of the Polygala obovata complex, with a taxonomic revision of the current names, was studied, recognizing three new species of Polygala for Brazil. The new species, Polygala capitolensis, P. jardimii, and P. paganuccii, are described, along with their diagnostic characters and notes on taxonomy. Distribution maps and photographic plates, including a comparative morphology, are provided.

Acaena (Rosaceae) is the most complex and ecologically variable genus in Sanguisorbinae. Although it has been the subject of several taxonomic treatments, the largest phylogenetic analysis to date only sampled a small fraction of the total global diversity (five to seven out of 45 to 50 species). This study included most of the species to elucidate the phylogenetic relationships of Acaena and biogeographic patterns in Sanguisorbinae. Phylogenetic analyses of non-coding nuclear (ITS region) and chloroplast (trnL-F) DNA sequence markers using maximum likelihood and Bayesian analyses suggested that Acaena is a paraphyletic group with species of Margyricarpus and Tetraglochin nested within it. We identified strong support for eight subclades that are geographically or taxonomically structured. Nevertheless, the species-level relationships within subclades are still uncertain, which may be due to rapid diversification and lack of informative characters in the markers used. Sanguisorbinae, a primarily Southern Hemisphere clade, exhibits a classic Gondwana disjunct distribution. This current distribution is explained primarily by eight long-distance dispersal events. Our results suggested that Sanguisorbinae split into Cliffortia and Acaena around 13.6 mya. While Cliffortia diversified in southern South Africa, Acaena experienced several migration events in the Southern Hemisphere. Our estimation of the ancestral range suggested that Acaena likely originated in South Africa, followed by migration and subsequent diversification into southern South America. From there, the genus migrated to New Zealand, throughout the Andes, and to tropical areas in Central America, reaching as far north as California. Chile and New Zealand are the main sources of propagules for dispersal as well as the greatest diversity for the genus. The evolutionary relationships of species in Acaena combine a history of rapid diversifications, long-distance dispersals, and genetic variation within some taxa. Further research should be undertaken to clarify the infraspecific classification of A. magellanica.

A new species of Phyllanthus with phylloclades endemic to the State of Bahia is described here. Phyllanthus dracaenoides can be recognized for its peculiar habit that resembles a species of Dracaena, a very unusual height of up to 7 m, the plagiotropic phylloclades spirally arranged, and its vermiform cincinni. Notes on its habitat, taxonomic affinity, conservation status, geographic distribution, illustrations, and photographs are provided.

Specimens attributed to Myrcia chytraculia and associated species form a complex within M. sect. Calyptranthes, occurring sympatrically throughout the Caribbean and Central America and sharing a continuously variable suite of morphometric traits. To ascertain whether species within this complex should be treated as separate or conspecific taxa, seven morphometric traits and a further two discrete characters are analysed using univariate and multivariate statistics. Leaf size and shape are found to be indicative of subspecies, and significant mean differences of traits can be found between groups, though they overlap throughout the range of the M. chytraculia complex. As a result of these findings, updated taxonomy for this group is proposed, creating the new combinations Myrcia chytraculia var. americana, Myrcia chytraculia var. pauciflora, and M. chytraculia var. zuzygium, as well as seven new synonyms. A distribution map and a key to the new varieties are also included.

Myrcia longipetiolata, a new species of Myrcia, is here described and illustrated. With a phylogenetic hypothesis, we show that this species belongs to Myrcia clade 10, a morphologically recognized and narrowly distributed group of species, which was recently discovered. Myrcia longipetiolata resembles M. unana due to its long leaves, acute or acuminate leaf apex, cuneate leaf base, long petioles, and they share the same area of occurrence. Myrcia longipetiolata differs from M. unana by its larger leaves, larger number of leaf secondary veins, marginal vein more distant from the leaf margin, lanceolate bracteoles, smaller and truncate, rounded, or apiculate calyx lobes with whitish to yellowish trichomes, and smaller floral disc. Besides the phylogenetic placement of M. longipetiolata within the genus, morphological comparisons with related species and comments on its distribution, habitat, and conservation status are also provided.

Recent fieldwork in the Sierra Martín García in southwestern Dominican Republic has yielded a new species of the American clade Castela (Simaroubaceae), Castela senticosa sp. nov., from seasonally dry tropical forest. This species has been collected from two separate localities, including Môle St. Nicolas in northwestern Haiti in 1929, but until now fertile material with both flowers and fruit was unknown. We provide a photographic plate and illustration, place it phylogenetically using plastome data, and compare it morphologically with close relatives. This increases the number of known species of Castela on Hispaniola from one to two, both of which are endemic but from different clades, and yields another species for the Greater Antilles, a known biodiversity hotspot and clear center of diversification for this group of arid-adapted, thorny shrubs. This work emphasizes that seasonally dry, tropical forests, although often understudied, house as yet undiscovered biodiversity and deserve far more comprehensive studies.

The family Malvaceae s. l. is a clade that comprises nine subfamilies. Phylogenetic relationships among them are not completely resolved and are inconsistent among studies, probably due to low phylogenetic informativeness of conventional molecular markers. In the present study, we provide new phylogenetic information for Malvaceae s. l. derived from newly-designed group-specific nuclear markers. By mining transcriptome data from the One Thousand Plants Project (1KP) and publicly available genome information from cotton, cacao, and Arabidopsis, we designed a set of molecular markers of potentially single- or low-copy nuclear genes for Malvaceae s. l. Phylogenetic potential of these new loci was compared to previously applied conventional markers (i.e. plastid trnK-matK region and rbcL gene and the nrDNA ITS region) using the phylogenetic informativeness method. The results show that, when the mined nuclear regions are used in combination, it is possible to resolve relationships at different taxonomic levels within the phylogeny. However, incongruence among nuclear loci is frequent in the group, explaining the prevalence of unresolved phylogenetic relationships.

Populations of Balanophora from southern China are often identified by local botanists as B. laxiflora based on their long cylindric male inflorescence, subsessile male flowers with slender rudimentary bracts, and subdiscoid synandria. In this study, we clarify the identity of seven such populations based on morphological characters and phylogenetic analysis using nuclear 18S and ITS ribosomal DNA sequences. We confirmed the occurrence of dioecious populations of B. yakushimensis and two previously unrecognized species, which we describe here as B. parajaponica and B. appressa. Phylogenetic analyses indicated that B. parajaponica, B. yakushimensis, B. appressa, B. laxiflora, and the agamospermic B. japonica, formed a well resolved clade, viz. the B. laxiflora clade. The four dioecious species, although highly similar in the morphology of male inflorescence and flowers, can be separated by leaf morphology and arrangement, ovary color, and arrangement of female flowers. The species limit of B. laxiflora, however, remains unresolved.

Relationships among members of Ericaceae subfamily Monotropoideae have been difficult to resolve due to reduction and convergent evolution in these parasitic plants. All species in this subfamily are fully mycoheterotrophic, meaning they obtain nutrients by parasitizing fungi rather than through photosynthesis. Here, we examine relationships and host specificity in one of the most widespread species in this subfamily, Monotropa uniflora. We use several lines of evidence to investigate whether there is support for recognizing a segregate, M. brittonii, as distinct. Based on molecular and morphological analysis of Monotropa collected throughout its range in the United States, we find two distinct lineages, one of which corresponds morphologically and geographically to Small's M. brittonii. We identified several morphological characters that differ between the two species. We also observed a high degree of fungal host specificity in M. brittonii, which appears to parasitize almost exclusively Lactifluus subgenus Lactariopsis section Albati. Additionally, M. brittonii was primarily collected from Florida scrub, which are xeric, shrub-dominated habitats that differ substantially from the mesic forests where M. uniflora typically occurs. Based on these molecular, morphological, and ecological differences, we support recognition of M. brittonii as distinct from M. uniflora.

Sanchezia dubia is described and illustrated as a new species from the department of Madre de Dios in southeastern Peru. Its morphology slightly resembles Sanchezia sprucei, but its most remarkable feature is its close similarity to Suessenguthia, even more so than to those of its own genus. This new species is distinguished from others by its glabrous stem and leaves, its inflorescence containing two to five serial cymose heads, which are sessile to short-pedunculate, with mostly two to four flowers each (occasionally one), its inner bracts ranging in length between 6 and 23 mm, and its androecium composed of two stamens and two mucronate staminodes. We suggest it is an endangered species based on its restricted geographic distribution, its few known populations, and the increasing threats to its habitats. Along with Suessenguthia koessleri, this new species seems to be a key taxon to understanding the phylogenetic relationship between these two genera, which is still uncertain. Additionally, we provide a key to identify the Sanchezia and Suessenguthia species of the Madre de Dios River basin from southern Peru to northern Bolivia.

Hyptidinae, ca. 400 species, is an important component of Neotropical vegetation formations. Members of the subtribe possess flowers arranged in variously modified bracteolate cymes and nutlets with an expanded areole and all share a unique explosive mechanism of pollen release, except for Asterohyptis. In a recent phylogenetic study, the group had its generic delimitations rearranged with the recognition of 19 genera in the subtribe. Although the previous phylogenetic analysis covered almost all the higher taxa in the subtribe, it lacked a broader sampling at the species level. Here we present a new expanded phylogenetic analysis for the subtribe comprising 153 accessions of Hyptidinae sequenced for the nuclear nrITS, nrETS, and waxy regions and the plastid markers trnL-F, trnS-G, trnD-T, and matK. Our results widely support the previous phylogenetic results with some changes in the support and relationship between genera. It also uncovers the need for a new combination of Eriope machrisae in Hypenia and the phylogenetic position of Hyptis sect. Rhytidea, which was demonstrated to be part of Mesosphaerum. The generic delimitation in Hyptidinae is discussed, and we recommend that further studies with more markers are needed to confirm the monophyly of Hyptidendron and Mesosphaerum, as well as to support taxonomic changes on the infrageneric delimitation within Hyptis s. s.

A new species, Espeletia ocetana (Asteraceae), from about 3500 m a. s. l. in Páramo de Ocetá, Mongua, Boyacá department, Colombia, is described and illustrated. The new species exhibits a caulescent rosette habit (0.7–1.8 m tall), sessile leaves, elliptic leaf laminae with greyish indumentum, robust bracteate thyrsoid capitulescences spreading laterally from rosette, each holding 16–37(–69) capitula, external phyllaries 14.2–31.1 mm long, and ray florets 13.9–21.3 mm long arranged in 2.0–2.9 series. It is markedly different from the majority of other members of the genus, and only slightly similar to E. jaramilloi, from which it can be easily distinguished by its taller stems, wider leaves with a smaller length/width ratio, and longer sheaths. Furthermore, E. ocetana has capitula with ray florets arranged in fewer series, and with longer phyllaries, ray corollas, ray corolla limbs, ray styles, ray style branches, disc florets, and disc styles. In addition, E. ocetana is distributed allopatrically in regard to E. jaramilloi, and differs as well in its ecological preference for humid to very humid shrubby páramos. Espeletia ocetana is rather abundant in its type locality, which is a relatively well-conserved páramo located within the limits of Parque Natural Regional Siscunsí-Ocetá. However, it is absent from road margins, abandoned agriculture fields, and other areas impacted by human activities. Further studies will be necessary to know appropriately the extent of the geographic distribution of E. ocetana, its ecological requirements and its phylogenetic affinities with other species.

The genus Solidago represents a taxonomically challenging group due to its sheer number of species, putative hybridization, polyploidy, and shallow genetic divergence among species. Here we use a dataset obtained exclusively from herbarium specimens to evaluate the status of Solidago ulmifolia var. palmeri, a morphologically subtle taxon potentially confined to Alabama, Arkansas, Mississippi, and Missouri. A multivariate analysis of both discrete and continuous morphological data revealed no clear distinction between S. ulmifolia var. palmeri and Solidago ulmifolia var. ulmifolia. Solidago ulmifolia var. palmeri's status was also assessed with a phylogenomic and SNP clustering analysis of data generated with the “Angiosperms353” probe kit. Neither analysis supported Solidago ulmifolia var. palmeri as a distinct taxon, and we suggest that this name should be discarded. The status of Solidago delicatula (formerly known as Solidago ulmifolia var. microphylla) was also assessed. Both morphological and phylogenetic analyses supported the species status of S. delicatula and we suggest maintaining this species at its current rank. These results highlight the utility of the Angiosperms353 probe kit, both with herbarium tissue and at lower taxonomic levels. Indeed, this is the first study to utilize this kit to identify genetic groups within a species.

The Atlantic Forest is the most species rich vegetation in Brazil and holds several phytophysiognomies, including the vegetation on inselbergs, which is a very stressful xeric environment that selects for very specialized biota. Cololobus is an endemic genus from Atlantic Forest inselbergs of eastern Brazil, and Cololobus ruschianus is a new species based on morphological evidence, differing from other species of the genus by its morphological traits in petioles, subinvolucral bracts, and outer involucral bracts. Cololobus ruschianus occurs in Santa Teresa, Espírito Santo State, Brazil and would likely be considered Critically Endangered (CR), based on the criteria of the IUCN red list.

A molecular phylogenetic investigation was carried out to clarify aspects of the systematics of Oxylobus, a primarily Mexican alpine genus of Eupatorieae. Analysis of sequence data from two nuclear (nrDNA ITS, ETS) and three plastid markers (rbcL, ndhF, matK) confirmed the monophyly of Oxylobus and placed species of Ageratina as its sister group. A survey of 56 samples of Oxylobus using nrDNA ITS and ETS provided support for the currently accepted species, and showed the recently described O. coyulensis to be distinct and the sister group to the rest of the genus. The results also confirmed the placement of O. juarezensis in synonymy with O. subglabrus. The results of a broad survey of Ageratina for ITS data showed that it is likely not monophyletic as currently circumscribed. The phylogenetic results also highlighted the distinctiveness of Piqueria and Piqueriopsis as a distinct clade at the base of Eupatorieae.

Praxelis scaturicola, a new Cerrado biome species, is described and illustrated. The main morphological features of this new species are: i) capitula usually isolated; ii) vinaceous involucral bracts; iii) reduced glabrous leaves well-spaced on the stem. This study also presents information on aspects of the new species' habitat, as well as field images and illustrations. Praxelis scaturicola is known only from the Paraúna municipality in Goiás state, Brazil. A key and comments on the Brazilian species of Praxelis are also presented with a special note on the status of P. grandiflora. Additionally, the synonymy of P. macrocarpa under P. capillaris is proposed.