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— Acalypha (Euphorbiaceae: Acalyphoideae) is a large, monophyletic genus distributed worldwide in tropical and subtropical regions, with a few species extending into temperate areas of southern Africa, Asia, and North and South America. We reconstructed phylogenetic relationships within the genus using DNA sequences from the plastid ndhF and trnL-F regions and the nuclear ribosomal ITS region, sampling 142 species to represent the geographic, morphologic, and taxonomic diversity with the genus, resulting in a 162 (158 in Acalypha) terminal and 3847 character combined dataset. Bayesian and maximum likelihood reconstructions based on the combined dataset yielded a tree with a generally well-supported backbone and several strongly supported clades. Our results strongly supported the monophyly of Acalypha subg. Acalypha as currently recognized but showed that A. subg. Linostachys and almost all other infrageneric taxa recognized in the most recent comprehensive classification of the genus were not monophyletic. We therefore propose a new subgeneric classification comprising A. subg. Acalypha, A. subg. Androcephala, A. subg. Hypandrae, and A. subg. Linostachys (s.s.). Our results also shed light on relationships within some species groups, including in what has been treated as a broadly defined A. amentacea, in which we recognize A. amentacea, A. palauensis comb. nov., and A. wilkesiana as distinct species. Bayesian ancestral state estimations based on the phylogeny of Acalypha demonstrated that inflorescence position and sexuality and habit show high homoplasy, especially within A. subg. Acalypha, and that inflorescence position and habit exhibit correlated evolution.

—We present a phylogenetic classification for Plukenetia (Euphorbiaceae, Acalyphoideae) based on morphology and molecular phylogenetic studies using nuclear (ETS, ITS, KEA1 introns 11 and 17, TEB exon 17) and plastid (matK, ndhF, psbA-trnH) DNA data. Plukenetia comprises 25 species divided into six sections, with three new sections and four new species described here. The circumscription of Plukenetia is unaltered from recent treatments and we continue to recognize Romanoa as distinct. The sections of Plukenetia correspond with the subclade system proposed by Cardinal-McTeague and Gillespie (2016): P1 = P. sect. Fragariopsis comb. et stat. nov.; P2 = P. sect. Penninerviae sect. nov.; P3 = P. sect. Plukenetia; P4 = P. sect. Angostylidium; and P5 = P. sect. Hedraiostylus + P. sect. Madagascarienses sect. nov. The sections are distinguished by a combination of leaf venation, staminate flower morphology, pistillate flower number, style morphology, fruit type, and seed size. Additionally, we describe three new species from South America belonging to sect. Penninerviae: Plukenetia brevistyla and Plukenetia megastyla from the Amazon basin and Plukenetia chocoensis from the Chocó Biogeographic Region of Colombia. The new Amazonian species are morphologically similar to P. brachybotrya but distinguished by their style shape and size. The new Colombian species is morphologically similar to P. penninervia but distinguished by its elongate basilaminar extrafloral nectaries, presence of abaxial laminar extrafloral nectaries, and longer inflorescences. We also describe a new species from sect. Plukenetia, Plukenetia sylvestris, which is found in central and southern Peru. This species is suggested to be the wild progenitor of the cultivated P. carolis-vegae, differing by its smaller seeds/fruits and fewer stamens. Molecular data, including a new ETS phylogeny sampling P. brevistyla, support our new taxa as distinct. Keys to the sections and species of Plukenetia are provided and we designate 12 new lectotypes for Plukenetia and Romanoa.

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 Wo...

The evolutionary history of the dracaenoid genera Dracaena and Sansevieria (Asparagaceae, Nolinoideae) remains poorly resolved, despite long-recognised issues with their generic boundaries and increased attention paid by both horticulturalists and taxonomists. In this study we aim to: (1) elucidate evolutionary relationships within and between Dracaena and Sansevieria using molecular phylogenetic inference of both nuclear (nDNA) and plastid (cpDNA) markers, (2) examine the infrageneric classifications of each genus, and (3) revise the circumscription of the dracaenoids in light of morphological and phylogenetic evidence. In total, we sampled 21 accessions of Dracaena (ca. 19 species), 27 accessions of Sansevieria (ca. 26 species), and six outgroup taxa. Phylogenetic analyses were based on nucleotide sequences of two non-coding plastid DNA regions, the trnL-F region (trnL intron and trnL-trnF intergenic spacer) and rps16 intron, and the low-copy nuclear region At103. Phylogenetic hypotheses were constructed using maximum parsimony, maximum likelihood, and Bayesian inference. Individual datasets were analysed separately and, after testing for congruence, as combined datasets. We recovered instances of soft incongruence between nDNA and cpDNA datasets in Sansevieria, but general trends in the dracaenoids were congruent, although often poorly supported or resolved. The dracaenoids constitute a strongly supported monophyletic group. Dracaena was resolved as a paraphyletic grade embedded with two clades of Sansevieria, a primary clade comprising most species, and a secondary clade including S. sambiranensis, a distinctive species from Madagascar. The backbone of our phylogeny was only resolved in nDNA analyses, but combined analyses recovered strongly supported species groups. None of the previous infrageneric classifications were supported by our phylogeny, and biogeographic groupings were frequently more significant than morphology. More work is needed to resolve internal relationships in the dracaenoids, but we support a recent proposal to recognise a broadened circumscription of Dracaena that includes Sansevieria. We provide a generic description for the recircumscribed Dracaena and new combinations for several species of Sansevieria in Dracaena.

Brassicales is a diverse order perhaps most famous because it houses Brassicaceae and, its premier member, Arabidopsis thaliana. This widely distributed and species-rich lineage has been overlooked as a promising system to investigate patterns of disjunct distributions and diversification rates. We analyzed plastid and mitochondrial sequence data from five gene regions (>8000bp) across 151 taxa to: (1) produce a chronogram for major lineages in Brassicales, including Brassicaceae and Arabidopsis, based on greater taxon sampling across the order and previously overlooked fossil evidence, (2) examine biogeographical ancestral range estimations and disjunct distributions in BioGeoBEARS, and (3) determine where shifts in species diversification occur using BAMM. The evolution and radiation of the Brassicales began 103Mya and was linked to a series of inter-continental vicariant, long-distance dispersal, and land bridge migration events. North America appears to be a significant area for early stem lineages in the order. Shifts to Australia then African are evident at nodes near the core Brassicales, which diverged 68.5Mya (HPD=75.6-62.0). This estimated age combined with fossil evidence, indicates that some New World clades embedded amongst Old World relatives (e.g., New World capparoids) are the result of different long distance dispersal events, whereas others may be best explained by land bridge migration (e.g., Forchhammeria). Based on these analyses, the Brassicaceae crown group diverged in Europe/Northern Africa in the Eocene, circa 43.4Mya (HPD=46.6-40.3) and Arabidopsis separated from close congeners circa 10.4Mya. These ages fall between divergent dates that were previously published, suggesting we are slowly converging on a robust age estimate for the family. Three significant shifts in species diversification are observed in the order: (1) 58Mya at the crown of Capparaceae, Cleomaceae and Brassicaceae, (2) 38Mya at the crown of Resedaceae+Stixis clade, and (3) 21Mya at the crown of the tribes Brassiceae and Sisymbrieae within Brassicaceae.

UNLABELLED PREMISE OF STUDY A monophyletic group composed of five genera of the Cleomaceae represents an intriguing lineage with outstanding taxonomic and evolutionary questions. Generic boundaries are poorly defined, and historical hypotheses regarding the evolution of fruit type and phylogenetic relationships provide testable questions. This is the first detailed phylogenetic investigation of all 22 species in this group. We use this phylogenetic framework to assess generic monophyly and test Iltis's evolutionary "reduction series" hypothesis regarding phylogeny and fruit type/seed number. • METHODS Maximum likelihood and Bayesian analyses of four plastid intergenic spacer region sequences (rpl32-trnL, trnQ-rps16, ycf1-rps15, and psbA-trnH) and one nuclear (ITS) region were used to reconstruct phylogenetic relationships among the NA cleomoid species. Stochastic mapping and ancestral-state reconstruction were used to study the evolution of fruit type. • KEY RESULTS Both analyses recovered nearly identical phylogenies. Three of the currently recognized genera (Wislizenia, Carsonia, and Oxystylis) are monophyletic while two (Cleomella and Peritoma) are para- or polyphyletic. There was a single origin of the two-seeded schizocarp in the ancestor of the Oxystylis-Wislizenia clade and a secondary derivation of elongated capsule-type fruits in Peritoma from a truncated capsule state in Cleomella. • CONCLUSIONS Our well-resolved phylogeny supports most of the current species circumscriptions but not current generic circumscriptions. Additionally, our results are inconsistent with Iltis's hypothesis of species with elongated many-seed fruits giving rise to species with truncated few-seeded fruits. Instead, we find support for the reversion to elongated multiseeded fruits from a truncate few-seeded ancestor in Peritoma.

That competition is stronger among closely related species and leads to phylogenetic overdispersion is a common assumption in community ecology. However, tests of this assumption are rare and field-based experiments lacking. We tested the relationship between competition, the degree of relatedness, and overdispersion among plants experimentally and using a field survey in a native grassland. Relatedness did not affect competition, nor was competition associated with phylogenetic overdispersion. Further, there was only weak evidence for increased overdispersion at spatial scales where plants are likely to compete. These results challenge traditional theory, but are consistent with recent theories regarding the mechanisms of plant competition and its potential effect on phylogenetic structure. We suggest that specific conditions related to the form of competition and trait conservatism must be met for competition to cause phylogenetic overdispersion. Consequently, overdispersion as a result of competition is likely to be rare in natural communities.

The family Cleomaceae is in need of taxonomic revision, which begins here with a set of taxa informally recognized as the North American cleomoid clade. This group is evaluated first because molecular-based analyses almost comprehensively sample this lineage. These investigations revealed that the two largest genera, Cleomella and Peritoma , are para- or polyphyletic. Strong support from molecular data necessitates name changes for these taxa. Furthermore, controversy exists on the recognition of the remaining genera, owing to morphological variation and specialization. Three possible classification scenarios are described to accommodate monophyletic lineages based on previously-published evidence. The option to create the single large genus Cleomella is proposed, and as a result one new name, Cleomella oxystyloides , is provided, and 12 new combinations are made: C. arborea , C. arborea var. angustata , C. arborea var. globosa , C. californica , C. jonesii , C. lutea , C. multicaulis , C. palmeri , C. platycarpa , C. refracta , C. serrulata , and C. sparsifolia . Two lectotypes and one isolectotype are designated, and another lectotype is confirmed.