The Neotropics are home to incomparable plant diversity. To evaluate the potential roles of geography and ecology on speciation in Neotropical plants we selected a small, tractable lineage of shrubby angiosperms, Piper subgenus Ottonia. We reconstructed a molecular phylogeny and provided insights into the species divergence times based on fossil calibration of the molecular clock. We support the monophyly of Piper subg. Ottonia and the two main lineages: Amazonian and Atlantic Forest, the latter containing the non-Atlantic species pair P. darienense—P. piscatorum. We also propose the origin of Piper subg. Ottonia in the early Eocene and suggest that the diversification of Piper subg. Ottonia was influenced by geo-historical events such as the Paleocene-Eocene Thermal Maximum (PETM) and the uplift of the Andes in the Miocene, as is the case for other angiosperms. Furthermore, we combined our phylogeny with geographic and environmental data in order to evaluate geographical and ecological contexts for speciation. We indicate that neither climatic/edaphic divergence nor geographic isolation appears to be needed to explain speciation in this lineage.

Dendrophylax porrectus is a leafless epiphytic orchid occurring in Florida (U. S. A.), the Greater Antilles, Mexico, Guatemala, and El Salvador. Previous morphological and phylogenetic analyses revealed considerable variation across its geographic range. This study examines morphological and molecular variation among populations of D. porrectus. Phylogenetic analyses of sequence data of nuclear (nrITS) and plastid (matK, ycf1) regions revealed several well-supported clades within D. porrectus. Molecular data and morphometric analyses of root thickness and floral parts support the recognition of two species within the D. porrectus clade. Dendrophylax megarhizus is described as a new species from Campeche, Jalisco, Veracruz, and Yucatán states of Mexico. A key to the species of Dendrophylax is presented.

Four new species of Habenaria restricted to the Espinhaço Range in the states of Minas Gerais and Bahia are described: H. reflexicalcar, H. hippocrepica, H. quadriferricola, and H. espinhacensis. Specimens were collected as long ago as 1816, but they were misidentified or unidentified in herbarium collections. Molecular phylogenetic analyses based on nuclear and plastid DNA sequences showed that these species form a highly supported clade, denominated Espinhacenses, which is related to other species having linear, grass-like leaves that are concentrated in the cerrado and campos rupestres vegetation of central and southeastern Brazil, although the closest relatives to the Espinhacenses clade were not resolved. There are no apparent morphological synapomorphies for the clade, it being characterized by a combination of characters, including slender plants, linear leaves, spiral inflorescences, few to many small and glabrous flowers, a pedicel that is shorter than the ovary, and separate hemipollinaria.

Stelis peruviana from the cloud forest of Yanatile, Cusco, Peru is described and illustrated. This new species is most similar to Stelis spathuliformis, from which it differs by its yellow flowers, shorter lanceolate sepals, and wider, shorter, obovate lip with irregular margins. Information on its habitat, phenology, and conservation status, as well as a key to the Peruvian species of Stelis previously classified in Pleurothallis subgen. Acuminatia sect. Acuminatae are given.

Zornia melanocarpa , a new species of Leguminosae (Papilionoideae, Dalbergieae) from Serra do Espinhaço, Minas Gerais, Brazil, is described and illustrated. The species is characterized by black fruits with white hairs and an absence of bristles, characters unique within the genus. The species is morphologically similar to Z. crinita and Z. hebecarpa, but differs from both by having a shorter inflorescence of 1.2–4 cm (vs. 10–20 and 8–20 cm in Z. crinita and Z. hebecarpa, respectively) and in the size of the plant (7–16 cm vs. 20–60 cm in Z. crinita and Z. hebecarpa), in addition to the black fruits with white hairs. A phylogenetic analysis using molecular data from the nuclear rDNA ITS gene region was performed to verify its position within the genus. Additionally, a survey of leaflet secretory structures and a micro-morphological analysis of fruit structures using scanning electron microscopy (SEM) was performed for the newly described species.

A new species of Crotalaria from Meghalaya (Northeast India) is described and illustrated. The new species is assigned to Crotalaria section Calycinae based on affinities to C. sessiliflora and C. occulta. The distribution, ecology, and conservation status of C. meghalayensis are briefly discussed. We also provide evidence from molecular data and statistical analyses to authenticate the distinctiveness of the new species.

Specimens of a new fruit genus and species, Alatonucula ignis, from the early Eocene Laguna del Hunco flora of Chubut, Patagonia, Argentina, have characteristics consistent with assignment to Juglandaceae. Each fossil fruit consists of a nutlet with an attached wing that varies from unlobed to trilobed. One specimen clearly shows that the nutlet has a single locule partially subdivided into four chambers; its counterpart contains a four-lobed locule cast. The basally partitioned locule with lobed seed indicates that Alatonucula can be placed within Juglandaceae; the overall structure of the fruits suggests affinities to subfamily Engelhardioideae, which typically have fruits consisting of a nutlet attached to a trilobed wing. Parsimony analyses of a morphological matrix for extant and fossil Juglandaceae revised from a previously published study demonstrate that 1) Alatonucula groups with Engelhardioideae; and 2) Paleooreomunnea, an Eocene North American taxon that includes a fruit type with a trilobed wing, is within crown-group Engelhardioideae. Alatonucula, along with fossil juglandaceous pollen from the Paleogene of Patagonia, indicates that Juglandaceae may have had an unexpectedly early presence in South America. Furthermore, these fruits represent a Laurasian biogeographic signal in the Laguna del Hunco flora, which contrasts with the predominantly Australasian signal highlighted in previous studies.

Tribe Plukenetieae (Euphorbiaceae, Acalyphoideae) is a pantropical lineage of mostly stinging, twining vines and lianas with diverse floral and pollen morphology. To elucidate generic relationships in the tribe and examine patterns of pollen morphology evolution, we conducted phylogenetic analyses of nuclear ribosomal ITS and plastid psbA-trnH DNA sequence and indel gap-scored data. We sampled all genera in subtribes Dalechampiinae and Tragiinae, and most in Plukenetiinae; species sampling was broad in the latter two subtribes. Our efforts produced a 2,207 character dataset of 154 terminals (representing ca. 93 species). Analyses of these data support the monophyly of each subtribe and weakly suggest Dalechampiinae (Dalechampia) is sister to Plukenetiinae Tragiinae. Within Plukenetiinae, Haematostemon is resolved as sister to Romanoa Plukenetia, and Plukenetia is divided into five subclades that mostly correspond to the current infrageneric classification. Tragiinae is resolved into an Old World lineage and a mostly New World lineage, and is divided into ten subclades also supported by floral and/or pollen morphology. Species-rich Tragia is recovered as para- or polyphyletic and intermixed with all other currently recognized Tragiinae genera. The recently segregated genera, Bia, Ctenomeria, and Zuckertia, are upheld, and Gitara is resurrected from Acidoton, resulting in two new combinations: Gitara nicaraguensis and Zuckertia manuelii. Pollen aperture and exine morphology are largely correlated with phylogeny. The loss of pollen endopores is a potential synapomorphy of Plukenetiinae Tragiinae, and we hypothesize that weakly defined apertures and inaperturate pollen originated independently four and three times, respectively.

Two new species of Caraipa from Colombia are described and illustrated: Caraipa antioquensis, endemic to Antioquia in the Andes and the only species of Caraipa occurring in this area, and Caraipa tumescens, endemic to Vaupés. Caraipa ferruginea is reported from Colombia for the first time. We also present an identification key and distribution maps for the 14 species of Caraipa in Colombia.

Geranium sect. Trilopha (Geraniaceae) consists of seven species: G. biuncinatum, G. brevipes, G. favosum, G. mascatense, G. ocellatum, G. trilophum, and G. yemense. The highest diversity of the group is located in Iran, the Arabian Peninsula, and adjacent regions of northeast Africa with five endemic species. One species occurs in the Himalayas and another is widespread in the mountains of tropical Africa. In contrast with current literature, we consider G. yemense to be a separate species from G. trilophum, and G. brevipes also to be separate from G. ocellatum. Micromorphological features of indumentum, pollen, mericarps and seeds were investigated by SEM. Two features are present in all species of the section and give strong support to this group: a) pollen with Erodium-type exine ornamentation (first reported here), and b) fruit with twisted rostrum. A new key is provided, as well as new and detailed descriptions. Each species is illustrated and mapped and five lectotypes are designated.

Calyptranthes is the largest clade of Myrcia s. l., and is a group of considerable diversity in the threatened Atlantic forest biome of Brazil, as well as in the Amazon, Caribbean, and Cerrado. Here an expanded, geographically and morphologically representative sample of Calyptranthes is tested for monophyly; the majority of species are shown to emerge as a monophyletic clade embedded within Myrcia s. l. A single species, Calyptranthes multiflora, emerges in an independent clade, suggesting wider non-monophyly. Patterns of relationships within the group are detected, and these correlate more closely with geography than with morphology, and suggest that the oldest lineages of Calyptranthes are from what is now the Amazon forest, with later radiations to the Caribbean, Atlantic forest, and Cerrado biomes.

The endemic New Caledonian genus Storthocalyx is only known from two of this South West Pacific archipelago's main vegetation types, maquis and humid evergreen forest, and within the latter it occurs on both ultramafic and volcano-sedimentary substrates. Recent phylogenetic studies confirm its monophyly and indicate that it forms a clade with two other endemic genera, Gongrodiscus and Podonephelium. Storthocalyx is characterized by leaflets with a glaucous lower surface (due to the presence of papillae) and a lack of domatia, actinomorphic flowers, distinct sepals, petals with many long trichomes and lacking appendages, and a three-locular capsule whose inner surface is covered with a dense indument. As part of a collaborative effort to clarify the taxonomy of New Caledonian Sapindaceae, a revision of Storthocalyx is presented. Species delimitation is based on results from a recently published multivariate morphometric analysis, and descriptions were prepared using the resulting data matrix coupled with examination of all available herbarium collections and extensive field observations. Five species are recognized, including one that is newly described (Storthocalyx corymbosus). A key to species is provided, along with descriptions, distribution maps, color photos, a line drawing (for the new species), and risk of extinction assessments following IUCN red list categories and criteria.

In this paper we describe and illustrate a new species of Simaba from the sandy coastal plains in northeastern Brazil, and discuss the controversial limits of the three sections proposed in the genus by Englerian classification. Simaba arenaria has a restricted distribution: it is known only from two small, somewhat disturbed areas, in restinga vegetation of Bahia and Sergipe states. The evaluation of its threatened status indicates that it is an endangered taxon, according to the IUCN Red List categories and criteria. We also provide novel data on the seedling of this species.

Hexasepalum is the priority name for Diodella. In the present paper, we provide a synopsis of Hexasepalum. The genus differs from the remaining genera of the tribe Spermacoceae by the combination of infundibuliform flowers, 2-lobed stigmas, schizocarpic fruits, ventral face of the mericarps with two depressions, seeds with T or Y shaped ventral grooves, and pollen grains with two types of supratectal elements. We propose two combinations, i.e. Hexasepalum domingense and H. vaginale, and the formal synonymization of H. angustifolium (including Diodella crassifolia). We also propose two new synonyms: Diodia rosmarinifolia [= Diodella rosmarinifolia] is placed in the synonymy of H. apiculatum, and Diodia incana is now considered a synonym of H. teres. We choose lectotypes for H. vaginale, and for two synonyms of H. apiculatum. In addition, we describe and illustrate a new species endemic from Bahia, Brazil, H. zappiae sp. nov. Detailed descriptions are provided only for the species imperfectly known; otherwise comprehensive taxonomic descriptions are mentioned for each species. The descriptions of the Hexasepalum species are complemented with a key, geographical distributions, and illustrations of key morphological characters. Line drawings are provided for species not illustrated before in literature.

The genus Ameroglossum was known only from A. pernambucense, a species found on inselbergs in the states of Paraiba and Pernambuco, Brazil. Ameroglossum manoel-felixii, a new species of Ameroglossum, is described and illustrated here, and morphologically compared with A. pernambucense. Information about the geographic distribution of the new species and karyotypic comparisons of both species using CMA/DAPI banding and nuclear DNA content are also presented.

Phymaspermum, the largest and most complex genus within the subtribe Phymasperminae, is revised and 17 species are recognised, all endemic to southern Africa. Four new species are described (P. aphyllum, P. comptonii, P. oppositifolium, and P. trifidum), five species are reduced into synonomy (P. bolusii, P. equisetoides, P. montanum, P. pubescens, and P. villosum) and P. thymelaeoides is recognized as the oldest available epithet for P. schroeteri. The species of Phymaspermum can be distinguished by a combination of habit, leaf, involucral, and fruit characters. Species relationships are assessed in a cladistic analysis of 12 anatomical and morphological characters. Phymaspermum is distinguished from Eumorphia and Gymnopentzia by the unique stalked myxogenic trichomes on the fruit surface. This character is shown to be a synapomorphy for Phymaspermum although subsequently lost in two species and replaced by resin canals in the fruit ribs. A comprehensive taxonomic treatment is presented, including a key to the species, correct nomenclature, typification, descriptions, and geographical distributions.

This study reports a new species of Domeykoa (Apiaceae; Azorelloideae) from the Andes of northern Chile. A detailed description and an illustration of the species are provided. Diagnostic morphological characters that distinguish it from similar species are its erect habit, fewer flowers per umbel, and opposite leaves. The new species is an erect annual or short-lived perennial herb, it is glabrous, up to 25 cm high, and is profusely branched close to the base. Its umbels are simple, sessile, or sub-sessile with three or four yellow flowers. DNA was obtained for molecular phylogenetic analyses. Bayesian analyses showed that the new species, D. andina, is nested within the previously recognized Clade Eremocharis-Domeykoa, as sister to D. amplexicaulis from the southern coast of Peru. This study confirms previous findings that neither of the two genera in the clade are monophyletic, raising questions about the nomenclature. The phylogeny also suggests an interesting Peru-Chile latitudinal disjunction of more than 500 km, also seen in other recently described species. However, a more complete phylogeny is needed to make conclusions on this matter. Based on IUCN criteria and categories, we suggest assigning a critically endangered (CR) category to Domeykoa andina.

The Daucus guttatus complex includes two to four species growing from central and northern Italy to the Middle East. They are characterized by being typically annuals up to 50 cm high; with primary umbels up to 7 cm in diameter with fewer than 25(35) rays; discolored umbels frequent, bearing one to several dark colored umbellules which form different color patterns; and mericarps relatively small, ca. 2.0–4.5 mm. The taxonomy of this complicated group has not been satisfactorily resolved to date and is the focus of current research. Seven names of species belonging to the D. guttatus complex occurring in the central and eastern Mediterranean basin are typified here: Daucus guttatus, Daucus bicolor, Daucus involucratus, Daucus setulosus, Daucus broteri, Daucus hirsutus, and Daucus speciosus. Historical data are reported to justify lectotype and/or epitype selection, and selected morphological and distributional data are used to facilitate identification. The resulting typifications will enable proper naming of clades identified in the accompanying integrated molecular and morphological study, clarifying the taxonomy of the Daucus guttatus complex.

In a previous study using 94 nuclear orthologs, we reported the species status of the Daucus guttatus complex to be unresolved, partitioned into three clades. In the present study, a subset of ten of these 94 orthologs was used to infer the phylogeny of the D. guttatus complex and related species. A near parallel set of accessions, planted in a common garden, was used for morphological analyses. The molecular trees are highly resolved for most of the clades, grouping accessions of the D. guttatus complex into four clades. Bayesian concordance analysis and a coalescent approach gave slightly different topologies. Morphological data likewise support four taxa in the complex. Moreover, herbarium research from a companion study informs nomenclature for taxa of the complex. We identify these four clades as D. bicolor, D. conchitae, D. guttatus, and D. setulosus; internested in or among these segregates are the phenetically distinctive species D. glochidiatus, D. involucratus, D. littoralis, and D. pusillus. Our research redefines species variation in the D. guttatus complex, clarifies species names, interspecific relationships, confirms a useful subset of nuclear orthologs for studies of dominant topologies of Daucus, and discovers morphological characters allowing proper identification of the four species of the D. guttatus complex and related species.