The phylogenetic relationships among members of the Neotropical clade of Miliuseae were inferred using Bayesian inference, maximum likelihood, and parsimony on a dataset of six plastid regions (ndhF, matK, psbA-trnH, rbcL, rps16-trnQ, and trnL-F). The phylogenetic hypothesis obtained indicate that the Neotropical clade of Miliuseae is a monophyletic group, composed of two distinct lineages: the first comprises the genera Sapranthus and Tridimeris, and the second is composed of Desmopsis, Stenanona, and two potentially new taxa, which together form the Desmopsis-Stenanona clade. However, the relationships within the Desmopsis-Stenanona clade are not fully resolved; the phylogenetic results indicate that Desmopsis and Stenanona, as currently circumscribed, are not monophyletic. The morphological characteristics that distinguish each genus and potential synapomorphies are discussed. We conclude that the observed variation in floral and fruit characteristics among the members of the Desmopsis-Stenanona clade could be driven by interactions with their main pollinators and fruit dispersers. Based on these results we propose that the Neotropical clade of Miliuseae needs to be recognized at the subtribe level, under the name of Sapranthinae.

A new orchid species from the Chihuahuan Desert region in Tamaulipas, Mexico and Texas, U. S. A., is described and illustrated. The phylogenetic position of the new species was assessed by parsimony and maximum likelihood analyses of nuclear (ITS) and plastid (matK-trnK, trnL-trnF) DNA sequences of 61 species/35 genera of Spiranthinae and 15 additional species and genera of Cranichideae. The results indicate a close relationship of the new species to several species previously included in Schiedeella, especially S. wercklei, but our analyses also show that such a group does not belong to the clade that includes the type species of Schiedeella (S. transversalis), being instead sister to Mesadenus. A new genus, Greenwoodiella, is proposed to include the new species (G. deserticola) and its closest relatives (G. micrantha var. micrantha, G. micrantha var. garayana, and G. wercklei). The identity of Lexarza's Neottia micrantha is clarified, the other species belonging in this clade are discussed, and the required transfers made. An identification key to the three species and two varieties we recognize in the new genus is provided.

Tetraglochin is distributed along the Andes from Peru to southern Argentina and central Chile. In order to test its monophyly and analyze relationships among species of this genus and allied genera, we conducted morphological studies and phylogenetic analyses using both nuclear (ITS) and cpDNA (trnL-F) sequences. As a result, Tetraglochin is supported as monophyletic, with the genus Margyricarpus as its sister group. Tetraglochin acanthocarpa and T. caespitosa are sister to the rest of the genus, which is grouped in two clades. One clade grows primarily distributed along the Central Andes, includes T. cristata, T. inermis, plus some specimens of T. ameghinoi, and has a coriaceous or papery and non translucent hypanthium. The other clade is mainly in the Southern Andes, contains T. alata and some specimens of T. ameghinoi, and has a membranous translucent hypanthium. Based on results obtained from morphological studies, molecular phylogenies, and species delimitation analyses, a new species T. andina, is proposed, segregated from T. ameghinoi. A key to identify all species herein recognized, and a map containing geographical distribution of them are provided, together with a description and illustration of the new species.

Based on phylogenetic analyses using rDNA and plastid sequence data, and the examination of morphological characters, we infer that Pleurostylia, as currently delimited, is a polyphyletic group. Pleurostylia serrulata and two newly described species from Africa are part of the New World Crossopetalum lineage. By contrast, Pleurostylia s. s. consists of all remaining species, which form a clade nested within a primarily Malagasy lineage. We present preliminary evidence that Pleurostylia opposita, the most geographically widespread species in the entire Celastraceae family, may include cryptic species. Although molecular evidence supports the monophyly of Crossopetalum, this genus does not appear to be well defined by a single morphological synapomorphy, rather the following combination of character states is diagnostic: 4-merous flowers; stamens inserted in the sinuses of a ± 4-lobed intrastaminal floral disk; pistil (2- or) 4-locular with one atropous ovule per locule; stigma conspicuously (2-) 4-branched; drupe usually single seeded and asymmetric with an excentric style remnant; and seeds exarillate with ramified postchalazal bundles visible on the surface and with endosperm present. A taxonomic treatment of Crossopetalum in Africa is presented, in which the new combination Crossopetalum serrulatum is proposed and two new species, C. bokdamii and C. mossambicense, are described and their conservation status assessed.

A comprehensive picture of how plant species and communities move and evolve over time will require that a variety of species be studied, including plants with different life histories, rarity, and distributions. Relatively few phylogeographic studies have focused on trees. In the present study, the phylogeographic history of Tilia americana, American basswood, was investigated. Samples were collected from throughout the United States and Mexican ranges of basswood, and a phylogenetic analysis was conducted based on sequence data from two non-coding chloroplast DNA regions. The results showed no evidence for the various hypotheses of multiple basswood species within the U. S. A., but there is evidence for a divergence between a Mexican and U. S. A. clade within basswood. Population genetics and spatial statistical analyses were also performed, and supported the conclusion that the only significant geographic barrier within the North American basswoods is found between U. S. A. and Mexico. An attempt was also made to interpret the anomalous geographic distribution of certain chloroplast haplotypes, raising further questions about past migration routes of North American temperate forest trees.

The pollen fertility of F₁ hybrids, ranging from progeny within natural populations to synthetic hybrids between species of Tolpis from three archipelagos in Macaronesia, was determined. Pollen fertility of F₁ hybrids of inter-archipelago crosses from the Azores, Canaries, and Madeira were generally lower than crosses between populations or species in the same archipelagos. Lower pollen fertility was pronounced in hybrids between plants from the Canaries and the other archipelagos, which is concordant with a more distant phylogenetic relationship between the Canaries, and the Azores and Madeira. Lower average pollen fertility was seen between plants from different as compared to the same clades in the Canary Islands. However, low pollen fertilities were also detected between plants from some populations/species in the same archipelagos, and even among progeny of individual maternal plants. Some hybrids with reduced fertility had meiotic irregularities, suggesting chromosomal rearrangements; in other cases meiosis appeared normal. Results indicate that postzygotic isolating factors evolved subsequent to the divergence of Tolpis in the three archipelagos, but there are hybrid sterility factors among plants within each of the archipelagos, and even within some natural populations. Phylogenetic relationships in the Canary Islands indicate that divergence has occurred within the last million years. Present results implicate postzygotic factors as reproductive barriers facilitating population divergence and speciation in Macaronesian Tolpis.

A new species of gemmiferous clubmoss, Huperzia continentalis, is described. This species is most abundant in northwestern North America, but also occurs in Greenland, northern Europe, and northeastern Siberia. Material of this species was previously treated as Huperzia haleakalae, but detailed morphological study shows that the species differ by color, leaf size and shape, and gemma distribution. With the recognition of Huperzia continentalis, H. haleakalae is only known from the type, collected on Maui in 1840, and is likely extinct. Huperzia continentalis is also compared to similar species of Huperzia with which it co-occurs; it is readily distinguished from these taxa by plant size, leaf dimensions, and the size and distribution of gemmae. Hybrids between H. continentalis and four other Huperzia species are discussed.

A new species from the highlands of southern Brazil, Ceradenia maackii, is described and compared to its most similar species. The new species is characterized by having small fronds, ciliate rhizome scales, petiole, axes, and laminar tissue without setae, and laminar tissue bluish and densely covered by glandular hairs. Ceradenia maackii is epipetric and known only from “Pico do Paraná” State Park. The new species is illustrated, and a key for Ceradenia from the Atlantic Rain Forest is also provided.

Adiantopsis alata was described by Prantl in 1883 and was distinguished from A. radiata based on the presence of large adaxial carinae along the stipes. Morphological and molecular analyses of specimens meeting this general description reveal four distinct species, with one endemic to eastern Brazil and three others restricted to the Guiana Shield. The syntypes for A. alata represent two different species, one from Brazil and the other from Guyana. Here, we designate a Brazilian syntype as the lectotype for A. alata and describe and illustrate three new palmate species from the Guiana Shield with adaxial carinae along their stipes: A. aurea, A. hickeyi, and A. scalariformis. A distribution map for the new species and a key to all ten palmate members of Adiantopsis are provided.

A new species of Brachionidium from Costa Rica is described and illustrated. Brachionidium cornu-nigricum, from the Volcán Cacho Negro, a remote, previously unexplored location in Costa Rica, is most similar to B. filamentosum. It differs in the white sepals, short-acuminate sepals and petals up to 1 cm long, the triangular, unlobed lip, the oblong glabrous callus provided with two small basal lobes, and the eight pollinia.

Spiranthes (Orchidaceae) is a primarily North American genus that has traditionally presented numerous taxonomic challenges. Many species display marked intra-species morphological variation and/or inter-species morphological similarities, such that cryptic speciation may be common. Molecular phylogenetic, morphological, field, and herbarium research concerning the delimitation of Spiranthes odorata necessitates the reinstatement and redescription of Spiranthes triloba, a name alternately synonymized under Spiranthes cernua and Spiranthes odorata for more than a century. While lost under synonymy, plants matching the morphology of Spiranthes triloba were ambiguously described as Spiranthes ×itchetuckneensis and Spiranthes ×folsomii, and these are here synonymized. Although the species has a descriptive specific epithet, the labellum of the holotype is decidedly not tri-lobed; Spiranthes triloba is redescribed and emended here so as to reflect its actual morphology. Spiranthes triloba is restricted to frequently burned calcareous prairies and flatwoods of Florida, and likely warrants protection at the state level. A key is provided to distinguish this species from other Spiranthes found in Florida, and a lectotype is designated for S. ×folsomii.

A new species of Telipogon, T. schneideri, is described and illustrated based on Colombian material. The newly described taxon is distinguished from T. falcatus by the lanceolate, non-falcate petals, which are conspicuously longer than the sepals, and by the lip that is densely covered by hispid hairs up to the margins. Information about habitat, ecology, and distribution of this new entity, as well as a brief discussion on closely related species are supplied.

Within the framework of a taxonomic revision of Drimia sensu lato we here describe a new species from the Eastern Cape Province in South Africa. Drimia trichophylla sp. nov. is at first sight related to D. vermiformis, but it can be clearly differentiated by the flower and leaf morphology and distribution. A complete description is presented for this species, and data on morphology, ecology, and distribution are reported. Affinities and divergences with other close allies are also discussed.

In order to understand the taxonomy of the enigmatic Tradescantia cymbispatha — the source of the confusion between T. sect. Austrotradescantia and T. sect. Cymbispatha — we reexamined the protologues of T. geniculata Vell., T. mundula var. scabrida, T. cymbispatha, T. cymbispatha var. villosissima, T. cerinthoides, T. koernickeana, and T. umbraculifera. Our analysis revealed a great deal of confusion caused by the misinterpretation of Vellozo's plate for T. geniculata. We concluded that T. cymbispatha is the accepted name for Vellozo's T. geniculata; Clarke's descriptions were based on a miscellaneous assemblage of three different species of Tradescantia from two different sections; and T. cymbispatha var. villosissima does not represent a distinct variety, but is a synonym of T. cerinthoides. Due to this confusion, a new Tradescantia species from Bolivia has remained undescribed until now. A table of morphological characters that distinguish the sections is also provided.

Merostachys is the second most species-rich genus of American woody bamboos, and can be recognized by the following combination of features: a solitary primary bud at the midculm nodes that later develops into a truncate or fan-shaped branch complement with numerous smaller subequal branchlets; pseudopetiolate culm leaves with reflexed blades; terminal, racemose synflorescences; and nucoid caryopses. In total, there are 51 described species; of these, 44 are found mainly along the Brazilian Atlantic coast, which is the center of diversity and endemism of the genus. During fieldwork in eastern Minas Gerais state, two previously unknown species of Merostachys (M. espessae and M. fimbriolaminata) were collected and are here described as new and illustrated. Additionally, these species are included in a dichotomous key to the species of Merostachys in eastern Minas Gerais state.

A new species, Echeveria pistioides (Crassulaceae) is described from south of Morelia in the State of Michoacán, Mexico. The species belongs to Echeveria ser. Gibbiflorae due to its short or acaulescent stems inconspicuous among the large basal leaves of rosettes, paniculiform inflorescence, conical-urceolate corolla, and tricolpate pollen grains. Within Echeveria ser. Gibbiflorae, the closest morphological affinities of E. pistioides are with E. marianae from which it differs in the glaucous leaves with a different shape and size, fewer cincinni, smaller flowers, and the absence of corolla appendages at the base of staminal filaments. The species grows on steep, humid slopes with E, W, or NWexposure and the general type of vegetation consists of oak and pine forest with mesophyllous elements.

We describe and illustrate a new myrmecophytic caesalpinioid legume species, Tachigali spathulipetala, from the highly endangered Brazilian Atlantic Forest domain. The new species is morphologically similar to T. pilgeriana and T. beaurepairei, but differs in having heteromorphic but mostly spathulate petals, and domatia-like cavities or callosities at the base of leaflets. An identification key to the Atlantic Forest species of Tachigali is also provided.

Croton cupreolepis (Euphorbiaceae) is newly described from montane, evergreen forests of eastern Madagascar. It is distinguished by its coppery-lepidote trichomes that form a dense covering on the floral buds and inflorescences, as well as on the dorsal side of the petals of both pistillate and staminate flowers, and also by its distinctive recurved pedicels. The young leaves are covered by the same type of coppery trichomes on the lower surface, but as the leaves expand, the coppery scales become scattered on a background of silvery scales. The species has been confused with Croton chrysodaphne, C. nobilis, or else specimens have been left determined just to genus. Its broad latitudinal distribution in Madagascar suggests that it may once have been more widespread, but has been a victim of the widespread deforestation of primary forest along the eastern slopes of the island.

Manihot species usually exhibit a shrubby habit, clambering or sprawling, or more rarely an arboreal habit. However, clambering or vine-like shrub species are little known and found mainly in South America. As part of the taxonomic treatment of the genus in the Midwest Region of Brazil, we discovered a new vine-like species growing in areas of Cerrado s. s. in the Chapada dos Guimarães National Park and neighboring areas. The new species, Manihot scandens, is described and illustrated here. Also, its geographical distribution, flowering and fruiting, conservation status, and morphological relationships are discussed. Additionally, we provide a key to all the vine-like species of the genus.

A new species of Dalechampia from Brazil is described and illustrated. Dalechampia erythrostyla is a twining vine and forms relatively dense populations in a disturbed area of the Atlantic Forest, where it has been facing a high risk of extinction. This species is superficially similar to D. alata, D. papillistigma, D. pentaphylla, D. purpurata, and D. violacea, but it differs from them in multiple morphological aspects, including leaf division, size of petiolar stipules and stipels, leaflet shape, number and color of lobes of involucral bracts, number and margin of pistillate sepals, color, size, and shape of stigma.

Two new hemiepiphytic species of Clusia (C. ucamira and C. lutea) from the Amazon Forest are described and illustrated. We provide a table with the major differences between C. ucamira and the similar species C. obovata and C. octandra. Clusia lutea is a distinct species with unclear relationships. Photographs as well as scanning electron microscopy images and distribution maps for the new species are also provided. Furthermore, we propose two new combinations and an updated synonymy for some Clusia species.

Recent molecular phylogenetic studies of Commiphora (Burseraceae) have revealed a complex history of species evolution in this genus, which includes four separate invasions of Madagascar. Two of these invasions have resulted in radiations of species that are not wellcharacterized taxonomically due in part to a lack of sufficient herbarium collections. Recent work has also revealed that morphological characters that have been used historically to circumscribe species of this genus have proven insufficient for distinguishing the closely related Malagasy species of these radiations. In this study we present a partial taxonomic revision for the most species-rich of these clades, the ‘Rhynchocarpa’ clade, which contains at least 26 species united by numerous molecular synapomorphies yet lack a shared, derived suite of morphological traits. Here, we revise seven ‘Rhynchocarpa’ species that are united by the presence of stellate pubescence on vegetative and reproductive parts of the plant, a trait that is uncommon in the genus and a practical metric for limiting the scope of the revisionary work. We include five new species, including four new names (Commiphora andranovoryensis, Commiphora elliptica, Commiphora morondavensis, and Commiphora razakamalalae) and a name currently in use, correctly published (Commiphora falcata). We provide morphological descriptions, distributional information, and conservation assessments for these as well as Commiphora aprevalii and Commiphora stellulata. We designate a lectotype for Commiphora stellulata. A key to the seven species is included. We envision this contribution as the first in a series of clade-based revisions that clarify the taxonomy of Malagasy Commiphora.

In preparation for a comprehensive nomenclatural review of the genus Argyreia, several unknown species were discovered. Thailand is a center of distribution for this speciose tropical Asian genus; three new Thai species, A. ankylophlebia, A. dokmaihom, and A. inaequisepala are described as a precursor to the nomenclatural review. Detailed descriptions, illustrations, and keys to species, modified from the Flora of Thailand Convolvulaceae account, are provided for each species to aid in their identification.

Three new species of Deprea, found in Ecuador and Peru, are described and illustrated. Deprea pauciflora has close morphological affinities with D. sachapapa, from which it is readily distinguished by the hirsute leaves, heterodynamous stamens, and invaginatepyriform fruiting calyx always loosely enveloping the berry. Deprea pecaensis shows similarities to D. maculatifolia, D. dilloniana, and D. pumila, although it is characterized by a combination of 1–3 flowers per node, narrowly elliptic leaves without any white macules, corolla lobes-tube length ratio 1.5: 1.75, homodynamous stamens, non-mucronate anthers, exserted style, and membranous leaves. Lastly, D. zakii is similar to D. hawkesii and D. purpureocarpa, but it can be distinguished by a combination of a glabrous to glabrescent vegetative indumentum, a campanulate corolla with revolute lobes which are equal to or shorter than the corolla tube, short calyx lobes, and staminal filaments broadening gradually in width basipetally. Discussions on taxonomy, geographic distribution, and conservation status are provided, as well as an identification key to the 50 species of Deprea.