Across the tree of life, molecular phylogenetic studies often reveal surprising relationships between taxa with radically different morphologies that have long obscured their close affiliations. A spectacular botanical example is Rafflesia, a holoparasite that produces the largest flowers in the world, but that evolved from tiny-flowered ancestors within the Euphorbiaceae. Outside of parasitic lineages, such abrupt transformations are rarely seen. One exception involves the “maidenhair ferns” (Adiantum), which are quintessential ferns: beautifully dissected, terrestrial, and shade loving. The closely related “shoestring ferns” (vittarioids), in contrast, have an extremely simplified morphology, are canopy-dwelling epiphytes, and exhibit greatly accelerated rates of molecular evolution. While Adiantum and the vittarioids together have been shown to form a robust monophyletic group (adiantoids), there remain unanswered questions regarding the monophyly of Adiantum and the evolutionary history of the vittarioids. Here we review recent phylogenetic evidence suggesting support for the monophyly of Adiantum, and analyze new plastid data to confirm this result. We find that Adiantum is monophyletic and sister to the vittarioids. With this robust phylogenetic framework established for the broadest relationships in the adiantoid clade, we can now focus on understanding the evolutionary processes associated with the extreme morphological, ecological, and genetic transitions that took place within this lineage.

We describe and illustrate a new species, Asplenium pifongia., currently known only from Taiwan. Although superficially similar to A. monanthe., this species is a sexual diploid and has little perforation on its spore surfaces. Phylogenetic analyses demonstrate that A. pifongia. is not closely related to A. monanthe., and is instead sister to the A. normal. complex. Asplenium pifongia. differs from A. normal. in having sori mostly only on, and parallel to, the basiscopic side of pinnae, a common feature in A. monanthes.

Previous studies have shown Homalomena as traditionally defined to be polyphyletic, with Neotropical species phylogenetically distinct from Asian species. This study of 29 accessions of 10 Neotropical taxa, and a total of 135 accessions representing 92 taxa of Homalomena, Furtadoa, and Philodendron for nuclear ITS and plastid matK regions, supports resurrection of the genus Adelonema for Neotropical species currently assigned to Homalomena. Adelonema is here delimited as a Neotropical genus of 16 species divided into two new sections: sect. Adelonema and sect. Curmeria, based on morphologically supported molecular results. The genus Adelonema is distinguished by a hypogeal rhizome, crushed vegetative tissues smelling of anise, an extensively sheathing, sometimes prickly petiole, chartaceous often variegated leaf blades, a spadix either obliquely inserted on the spathe/peduncle (sect. Adelonema), or stipitate (sect. Curmeria), ovaries with 2–4-pluriovulate locules, and anatropous ovules on an axile placenta. Four new species are described: Adelonema orientalis, A. palidinervia, A. panamensis, and A. yanamonoensis. Eleven new combinations are made: Adelonema allenii, A. crinipes, A. hammelii, A. kvistii, A. moffleriana, A. peltata, A. picturata, A. roezlii, A. speariae, A. wallisii, and A. wendlandii.

Considerable numbers of species have become extinct before being scientifically described, and the loss of natural habitats is known to be one of the major reasons for biodiversity declines. In this study, an endangered new species, Cayratia cheniana L. M. Lu & J. Wen, endemic to the limestone mountains of Ninh Thuan province of Vietnam is herein described based on both morphological and molecular evidence. With five chloroplast markers, Cayratia cheniana is placed as the first diverged lineage of Cayratia Juss. Morphologically, Cayratia cheniana shares synapomorphies with all other Cayratia s. s. in possessing a membrane enclosing ventral infolds in the seeds and presence of bracts on the lower part of the inflorescence axis. This species can be readily distinguished from other congeners by its tripalmate-trifoliate to bipinnate leaf architecture and stems with shredding bark.

Ant-plant mutualisms are abundant in the tropics and are popular models for ecological study, but investigating the origin and evolution of such systems requires a phylogenetic framework. A common ant-plant mutualism in the Neotropics involves the genus Cecropia, a group of fast-growing pioneer trees that are important in forest regeneration. Relationships between genera in the tribe Cecropieae (Urticaceae), including Cecropia, Coussapoa, Musanga, Myrianthus, and Pourouma, are unknown and are necessary to investigate the evolutionary history of the Cecropia-ant mutualism. Bayesian phylogenetic analyses of the NADH dehydrogenase (ndhF) chloroplast gene region, the 26S region of nuclear ribosomal DNA, and an exon-primed intron-crossing DNA region support the position of non-myrmecophytic African Musanga within a paraphyletic Cecropia. Neotropical Pourouma and Coussapoa are supported as sister taxa with African Myrianthus as their closest relative. Although it remains uncertain whether myrmecophytism was the ancestral condition of the Cecropia clade, a close relationship between non-myrmecophytic Cecropia sciadophylla and Musanga suggests that the loss of ant associations did not accompany African colonization.

Commiphora (Burseraceae) is the most species-rich genus in the frankincense and myrrh family, whose widespread and often remote distribution in seasonally dry tropical forests globally has impeded efforts to resolve its taxonomy and investigate its systematic biology. Here we focus on establishing the origin and evolution of Commiphora species native to Madagascar, all of which are endemic. Recent work has uncovered 16 new Malagasy species, bringing the total number of island endemic species to 44 and comprising nearly 25% of the genus. Previous phylogenetic studies of Commiphora have indicated that Malagasy lineages immigrated to and radiated within the island twice. We test this biogeographic hypothesis more thoroughly using a nearly comprehensive sampling of species from Madagascar, an expanded sampling of Commiphora species native to other regions, and a greater depth of DNA sequence data from the nuclear (nrETS, nrITS) and chloroplast (psbA-trnH, ndhF-rpl32, and trnD—trnT) genomes. Results from this expanded phylogenetic analysis include strong support for seven infrageneric clades within a monophyletic Commiphora, which we refer to as the ‘Lasiodisca,’ ‘Granulifera,’ ‘Saxicola,’ ‘Gariepensis,’ ‘Spinescens,’ ‘Arafy,’ and ‘Rhynchocarpa’ clades. Malagasy species comprise four distantly related lineages, including one species sister to all other Commiphora species (C. lasiodisca), the species-rich ‘Arafy,’ and ‘Rhynchocarpa’ clades, and one species embedded within the predominantly East African ‘Spinescens’ clade (C. simplicifolia). We describe the morphological and geographic affinities of each infrageneric and Malagasy lineage and identify priorities for future systematic study of the genus.

Paradrymonia Hanst. (Gesneriaceae) with 40 currently recognized species is a genus of facultative epiphytic herbs that inhabits the forest understory. The genus occurs throughout the Neotropics except for southeastern Brazil and the Caribbean. Monophyly of neotropical Paradrymonia and species relationships within the genus and closely related genera were evaluated based on molecular sequence data from the nuclear ribosomal (nrDNA) internal and external transcribed spacer regions (ITS and ETS), and the plastid (cpDNA) psbA-trnH intergenic spacer. Traditional Paradrymonia is resolved as polyphyletic and includes taxa in three clades. The clade that contains the type species is recognized as Paradrymonia sensu stricto (s. s.) and includes three species. The Paradrymonia s. s. clade is sister to a clade that includes species of Nautilocalyx, Chrysothemis, and most of the species traditionally recognized as Paradrymonia. Morphological characters useful for circumscribing generic boundaries include bearded anthers, rosette habit, presence of leaf anisophylly, and lanceolate calyx lobe shape. Our results support the re-circumscription of Paradrymonia and the resurrection of two previously recognized genera, Centrosolenia and Trichodrymonia, in order to accommodate the remaining ex-Paradrymonia species. Forty-three new combinations (11 in Centrosolenia, four in Chrysothemis, and 28 in Trichodrymonia) are made. The genus Nautilocalyx is moderately supported as lacking monophyly, but broader taxon sampling is necessary before new generic circumscriptions are provided.

Veronica subgen. Pseudolysimachium constitutes a group of about 28 species across northern Eurasia, many of them with considerable intraspecific morphological variation. This intraspecific variation may be due to large geographical distribution area, wide ecological amplitude, or widespread hybridization and polyploidization. Several recent studies using molecular data have shown that hybridization as an explanation for generating evolutionary novelties and high intraspecific variation may be more common than previously thought. Here we investigate the importance of hybridization in generating morphological variation and blurring species boundaries in V. subgen. Pseudolysimachium using analyses of cpDNA sequences from 139 individuals from 18 species and ten putative hybrids, and pyrosequenced ITS1 nrDNA sequences from 37 individuals from 16 species and four putative hybrids. In addition, we estimated ploidy levels for 42 individuals of ten species and five putative hybrids using flow cytometry. Analyses of cpDNA did not resolve phylogenetic structure (most of the species were polyphyletic). Our second approach, pyrosequencing of ITS1, generated up to nine different unique sequences per individual and phylogenetic analyses of the dataset resolved some basal nodes but, again, species were often non-monophyletic. The results are most compatible with a scenario of an East Asian origin and repeated spread across Pleistocene Eurasian steppes, known as important plant diversification center, with frequent interspecific hybridization. We compare the applicability of these molecular regions for resolving hybridizing species complexes and specifically address hypotheses of hybrid origins for several species within the subgenus. However, any population genetic, phylogeographic or other analysis of evolutionary questions in one species alone would be futile without considering introgression from related species.

The 12 species of Solanum sect. Micracantha are part of the large subgenus Leptostemonum or “spiny solanums,” which includes some 350–400 species. Members of the section are found in the Neotropics and are characterized by a combination of characters including a viny, climbing habit using recurved prickles, unbranched inflorescences, deeply divided corollas, and glabrous fruits. Broad-scale phylogenetic relationships within the spiny solanums have been the subject of several recent studies, but many of the individual groups, including sect. Micracantha, have received little attention. In this study we infer relationships within sect. Micracantha and its placement within the spiny solanums using DNA sequence data from three chloroplast markers, trnT-F, rpl32-trnL, and ndhF-rpl32 and five nuclear markers, ITS, waxy, and three COSII markers: At1g44760 (COS4b), At1g50020 (COS5c), and At2g15890 (COS5). Results support the monophyly of sect. Micracantha (the Micracantha clade) and its sister relationship with the Bahamense clade of the spiny solanums. Within sect. Micracantha it appears that characteristics such as fruit size and habit are more strongly correlated with the habitat in which the species grow than with the phylogeny. The COSII markers had numerous parsimony-informative characters and are similar in their utility to the more commonly used ITS and waxy markers. The trnT-F chloroplast marker resolved more nodes than the ndhF-rpl32 and the rpl32-trnL markers in parsimony analyses, despite the greater number of parsimony-informative characters in rpl32-trnL.

Four new Aristolochia species from the Mexican states of Colima, Jalisco, and Nayarit are described and illustrated. The four new species, Aristolochia nahua, A. pacifica, A. savannoidea, and A. tuitensis, belong to Aristolochia subsection Pentandrae, and are morphologically similar to A. buntingii and A. tresmariae. All of these species grow in the biogeographic province of the Mexican Pacific Coast, an important area of diversity and species richness of Aristolochia subsection Pentandrae.

The first detailed illustration of the type specimen flower of Selenipedium chica since Reichenbach's description of this species is presented and the actual staminode shape of this species is described. The infraspecific variation of S. chica is discussed and a new subspecies within this taxon, S. chica subsp. buenaventuraem, is proposed. Additionally, two new species of Selenipedium, S. garayanum and S. olgae, are described and illustrated. A key to the species of Selenipedium is provided.

Aspidistra cylindrica, a new species from southern Vietnam (Kon Tum province), is described and illustrated. The new species possesses a unique combination of cylindrical shape of pistil and shoot system with foliage leaves crowded in groups and not divided into petiole and lamina. Aspidistra cylindrica resembles A. muricata but differs in longer leaves, shorter and wider perigone, shorter pistil, shape and colour of perigone lobes, anther position, and stigma shape. The conservation status of A. cylindrica is assessed. A key for species of Aspidistra in southern Vietnam is provided.

Fimbristylis comprises about 300 species with pantropical and subtropical distributions, whose diversity is still being discovered. This study presents and describes three new species, Fimbristylis boldriniana, F. campestris and F. stipitata, and proposes lecto- and epitypification for Fimbristylis aspera from South America. In addition to complete morphological descriptions, we provide ecological information, geographic distribution, and conservation status for these species. This study provides the first identification key to all species of Fimbristylis that occur in Brazil.

Previous molecular phylogenetic analyses based on plastid DNA sequence data supported the recognition of Kuruna as a new temperate woody bamboo (Arundinarieae) genus, representing the twelfth major linage of Arundinarieae. Kuruna is distinguished by a combination of vegetative and reproductive characters including features of rhizomes, branching and synflorescences. Here seven species, distributed in Sri Lanka and southern India, are included in this genus: Kuruna debilis, K. densifolia, K. floribunda, K. scandens, K. walkeriana, K. wightiana (here transferred to Kuruna), and the newly described K. serrulata. This revision includes an updated description of the genus, detailed descriptions for all seven species, line illustrations for all species, and a morphological key for their identification.

The new species Syzygium dawsoniana is proposed for New Caledonia. It is characterized by its relatively large bullate leaves with a cuneate base and distinct petiole. It most closely resembles Syzygium guillauminii, which differs by its sessile to subsessile leaves having cordate or rounded bases. A preliminary conservation status of Endangered [EN] is suggested following IUCN Red List Categories and Criteria.

Paullinia species are generally laticiferous, woody climbers with a pair of watch-spring tendrils at the middle of the inflorescence, stipules, compound leaves with mostly pinnate organization, zygomorphic flowers with white corollas, septifragal capsules, and black or dark brown seeds with a white arillode. Paullinia is a Neotropical genus with approximately 220 species, one of which (P. pinnata) is also naturally found in Africa and Madagascar. Currently, 99 species are listed for Brazil, most of which are found in forest formations. The Amazon and the coastal Atlantic Forest are the two Brazilian biomes that hold the greatest diversity of Paullinia, with 73 and 26 species respectively. Surprisingly, nearly half of the Brazilian species of Paullinia (45 species, five new records for Brazil) are recorded for the Amazonian state of Acre. In the present work, we provide keys and brief species descriptions to identify the species of Paullinia found in the state of Acre. We also provide information on their distributions within Acre, and within their total range. It is noteworthy that about 70% of the species had their distribution restricted to the Amazonian domain and 44% are restricted to southwestern Amazonia, suggesting this region is a center of diversity for the genus.

A new species of Rubiaceae, Mycetia fangii, is described and illustrated from Guangxi, South China. The new species morphologically resembles M. mukerjiana but differs in the calyx bearing one short gland on each sinus, the calyx lobes much shorter than the corolla, and shorter bracts and bracteoles. It is one of the species with cauliflorous inflorescences in Mycetia. Further examination of herbarium specimens shows that M. apoensis, M. yatesii, and M. lanceolata (Ridl.) Ridl. (non Miq.) are conspecific with M. cauliflora, the type species of the genus. Thus the three names are here reduced to synonymy of the type species. A key to the species of the genus with cauliflory is provided at the end of this paper.

Randia brevituba is a new species of the Paranean region of Argentina and Paraguay. It differs from the closest species, R. ferox, which is sympatric, in having short corolla tubes of 4.7–5.4 mm in the pistillate flowers and 2.8–7.9 mm in the staminate flowers, calyx lobes varying in shape and size in the same pistillate flower, and globose fruits 14–17 mm long (versus corolla tubes of 25.0–27.0 and 22.6– 34.0 mm long, respectively, calyx lobes equal in shape and size, and fruit 3–5 cm and ovoid, ellipsoid or subglobose in R. ferox). We also discuss the taxonomic concept and geographic distribution of Randia armata, and conclude that it is markedly different from R. brevituba and the other species in the Southern Cone studied here, and moreover, that it does not occur in the Southern Cone. We provide a taxonomic key to distinguish the new species from other species of Randia in the Southern Cone of America.

Valeriana gaimanensis, a new species from Argentinean Patagonia, is described and illustrated. The new species belongs to the subgenus Valeriana and is apparently endemic to the Extra-Andean Patagonia region, where it grows in an extremely arid environment, in contrast to most Valeriana species distributed in Patagonia. The morphological relationships of V. gaimanensis are discussed in comparison with V. carnosa, which resembles the new species morphologically. Principal component analysis was performed with 28 morphological variables, including specimens of these two species, revealing differences between them. This study provides the distribution, habitat, phenology, and etymology of V. gaimanensis, as well as a key separating it from the other Valeriana species that inhabit Extra-Andean Patagonia.