Pinus chiapensis is a threatened species of pine from southern Mexico and Guatemala. It was first described as a disjunct variety of P. strobus from the eastern United States and Canada. Subsequent morphological work indicates that P. chiapensis is a distinct species, but this interpretation is controversial. To explore the distinctiveness of this taxon, we sequenced three low-copy, unlinked nuclear loci in multiple accessions of P. chiapensis and its three most probable progenitors (P. ayacahuite, P. monticola, and P. strobus). Pinus chiapensis had the lowest combined nucleotide diversity of the four species (0.0031), and had only a single allele rangewide at one locus. Pinus chiapensis does not share alleles with any of the possible progenitors and all of its alleles are monophyletic at two of the three loci. At the third locus, allelic nonmonophyly is statistically indistinguishable from monophyly. While our results show that P. chiapensis is at least as distinct as the remaining three widely accepted species, determination of the most recent common ancestor is complicated by lack of allelic monophyly within potential progenitors and interlocus variability. Based on our sample of individuals and loci, P. ayacahuite appears to be the least likely progenitor, but there is no clear resolution of whether P. chiapensis is more closely related to P. monticola or P. strobus.

A description and illustration of a new species of Licuala, L. hainanensis, from Hainan, China is given. This species, endemic to Hainan, was previously confused with the widespread L. spinosa. The distribution of the new species is mapped, and it is compared and contrasted to morphologically similar species from Vietnam. Evidence is presented that L. hainanensis is both dioecious and sexually dimorphic, based on its flower and rachilla morphology. Other potential cases of sexual dimorphism in Licuala are discussed.

The genus Zeugites P. Browne encompasses ten species of neotropical grasses. To infer the phylogenetic relationships of the species, parsimony analyses of morphological data and DNA sequences from a nuclear region (ITS) and two non-coding plastid regions (the trnL intron and the trnL-trnF intergenic spacer) were undertaken for each data set separately and in combination. The combined analysis is presented as our preferred phylogenetic hypothesis because of its better resolution and higher support for the clades. Zeugites is monophyletic only if Calderonella sylvatica is included in it. Our analyses recover two major clades within Zeugites: Clade I, formed by Zeugites pittieri, Zeugites latifolia, Zeugites sylvatica (Calderonella sylvatica), Zeugites sagittata, and Zeugites capillaris; and Clade II, including Zeugites hackelii, Zeugites smilacifolia, Zeugites munroana, Zeugites pringlei, Zeugites mexicana, and Zeugites americana. The monospecific genus Pohlidium is strongly supported as sister of Zeugites (including Calderonella) but it is maintained as a different genus due to noticeable differences in spikelet and inflorescence morphology.

Sequences of the chloroplast genes matK and rbcL and nuclear ribosomal ITS2 were used for phylogenetic analyses of Berberidaceae. Three major clades were recognized, corresponding to the chromosome base numbers x = 6, 7, and 8/10. Bongardia was sister to the clade containing Achlys and the Podophyllum group, which consists of Diphylleia, Sinopodophyllum, Podophyllum, and Dysosma. The estimated times of divergence of six disjunct genera between Eurasia and North America ranged from 7.5 ± 2.3 Ma to 1.0 ± 0.7 Ma. The intercontinental disjunct lineages of Berberidaceae may have originated in eastern Asia and then migrated to Europe and North America. However, long-distance dispersal may explain the distribution pattern of Achlys. Desert xerophytes of Berberidaceae in southwestern Asia originated in response to the advent of dry climate at different times; Bongardia diverged from its closest relatives at 46.5 ± 3.6 Ma, whereas Leontice differentiated from Gymnospermium at 10.3 ± 3.2 Ma.

Leandra hermogenesii (section Oxymeris), a new endemic species of Melastomataceae from São Paulo, Brazil, is described and illustrated. The distinguishing characteristics of the species include its leaves, which are subcartaceous, ovate to broadly ovate, 5(–7)-plinerved, 5.6–9.6 cm wide, and have a rounded base, its smaller bracts, bracteoles, and glabrous petals , and its larger ovary. A discussion and an identification key to morphologically related species are also presented.

The tribe Detarieae s.l. (Caesalpinioideae: Leguminosae) contains a large number of genera that produce resins, but which previously had been placed in differrent generic groups. To test the monophyly of the resin-producing Detarieae and to examine phylogenetic relationships among these genera, we analyzed sequences from the chloroplast trnL intron and trnL-F spacer for more than 80 taxa and from the nuclear ribosomal Internal Transcribed Spacers (ITS) for over 50 taxa. The two chloroplast regions were highly congruent, but incongruent with the nuclear ITS data. Incongruence may be the result of hybridization, particularly in the Colophospermum and Hardwickia polyploid lineage. Resin-producing taxa are scattered among two clades, the Prioria and Detarieae s.s. clades, which together are monophyletic, but only with weak support. This group is characterized by the ability to produce bicyclic diterpenes. The phylogenetic relationships as inferred from molecular data resolved the intergeneric affinities but the main clades obtained are different from the groupings proposed by classifications based primarily on morphological characters. Based on these analyses, we propose new generic groupings that correspond to the Prioria s.s., Hardwickia, Hymenaea, Eperua s.s. and Detarium clades.

Phylogenetic relationships among the genera Dalbergia, Machaerium, and Aeschynomene were investigated with sequences from both the chloroplast DNA trnL intron and the nuclear ribosomal DNA ITS/5.8S region. A parsimony and Bayesian analysis of individual and combined data resolved a monophyletic Dalbergia that is sister to a clade comprising Aeschynomene sect. Ochopodium and Machaerium. Aeschynomene sect. Aeschynomene is paraphyletic with respect to genera such as Bryaspsis and Soemmeringia, which collectively are sister to the Dalbergia-Machaerium-Ochopodium clade. This study identifies the disparate lineages of the genus Aeschynomene and reveals that species with basifixed stipules (i.e., sect. Ochopodium) perhaps should be ranked as a distinct genus. Species of Ochopodium have the general lomented fruit morphology in contrast to the unique indehiscent samara fruits of Machaerium. The findings of this analysis also have some bearing at the infrageneric level. Limited sampling of Dalbergia sects. Triptolemea and Ecastaphyllum resolves them as monophyletic. In contrast, the traditional infrageneric classification of Machaerium does not show much agreement with molecular groups. Additional sampling of Aeschynomene and Machaerium species, other DNA sequences, and morphological data are needed to resolve the exact relationship of sect. Ochopodium to Machaerium, as well as validate the infrageneric classification of Machaerium.

During a recent survey of Malagasy Garcinia, we uncovered several herbarium collections sharing the general floral morphology of G. verrucosa, the sole member of the Xanthochymus Group in Madagascar but differing in a number of leaf, flower and fruit characters. Further inspection of specimens deposited in herbaria particularly rich in Madagascar collections led us to conclude that these unassigned collections represent two new species of Malagasy Garcinia, which we describe here under the names, G. capuronii and G. lowryi. Garcinia verrucosa differs from both new species by having larger (≥ 8 vs. ≤ 5 mm long) flowers and fruits without ridges or lobes. Garcinia capuronii is easily distinguished from G. lowryi by its larger (26–41.4 vs. 1–10.5 cm long), bullate (vs. plane) leaf blades, and strongly 8-ridged (vs. shallowly (3)4-lobed) fruits. Based on IUCN criteria, the widespread G. lowryi should be considered a species of Least Concern (LC), whereas G. capuronii, a species known only from its type, is provisionally assigned to the Critically Endangered (CE) category.

A revision of the seven paleotropical species of Plukenetia (Euphorbiaceae) is given. Three sections or species groups are recognized. Two genera, Tetracarpidium (synonym Angostylidium) and Pterococcus, are treated here as sections of Plukenetia. The monotypic P. sect. Angostylidium includes the African species P. conophora, while P. sect. Hedraiostylus (synonym P. sect. Pterococcus) comprises two African species (P. africana and P. procumbens) and one Asian species (P. corniculata). A third species group restricted to Madagascar is distinguished by an androecium of sessile anthers on an elongate receptacle, and comprises three species, two described here. Plukenetia decidua, from southeastern Madagascar, is close to P. madagascariensis and shares styles partly fused into a cylindrical column, but differs in its narrower ovate or triangular-ovate leaf blades, smaller eglandular bracts, racemes with flowers single per node, and fewer anthers on a shorter ellipsoid receptacle. Plukenetia ankaranensis from northern Madagasar is distinguished from the previous two species by its styles entirely fused into an enlarged obovate stylar column. A key to the seven paleotropical species is provided and their relationship to neotropical species is discussed.

The genus Alchornea in the Malay Archipelago (= Malesia) and Thailand comprises only five instead of eleven species as recognized by current literature. They can be divided into two groups. One group, section Cladodes, with only one variable, widespread species (India to Australia) has obovate leaves and lacks stipellae (A. rugosa, including A. pubescens and A. petalostyla). The other group, section Stipellaria, has ovate leaves and stipellae. In this group, A. tiliifolius (including A. villosa) and A. parviflora (including A. borneensis, possibly A. adenophylla, and what was known as A. trewioides in Thailand) are widespread species (India to West Malesia); Alchornea sicca (including the Indochinese A. coudercii) is found in the Philippines and Indochina, and A. rhodophylla is only present on Penang Island in Peninsular Malaysia. The main distinguishing characters can be found in the indumentum, shape of the leaves, stipellae, roughness of the ovaries and fruits, size of the bracts and pistillate sepals. Alchornea trewioides, formerly recorded for Thailand, extends only to S.E. China and N. Vietnam; it can be distinguished from the closely similar A. liukiuensis from Taiwan and the Ryukyu Islands.

This study investigates species boundaries in the polyploid complex of Rosa sect. Cinnamomeae east of the Rocky Mountains. This complex is characterized by extensive intra-specific polymorphism that is the consequence, in part, of hybridization and polyploidy. An objective multivariate approach is employed to delimit species in the complex, which involved cluster and ordination analyses of 25 quantitative morphological characters and of amplified fragment length polymorphisms (AFLPs). Because polyploid individuals blurred species boundaries in the complex, they were discriminated a priori using stomata guard cell lengths in order to investigate species boundaries at each ploidy level separately. Four distinct species were found at the diploid level: R. blanda – R. woodsii, R. foliolosa, R. nitida and R. palustris. According to the morphological and molecular data, R. blanda and R. woodsii are indistinguishable and should be considered as a single species. Three species were identified at the polyploid level, R. arkansana, R. carolina, and R. virginiana, albeit with evidence of hybridization between them. The genetic and morphological similarity between individuals of the polyploid species and those of the different diploid species allowed us to identify possible parents for the polyploid species. Rosa arkansana likely originated from R. blanda (incl. R. woodsii), R. carolina from a hybrid between R. blanda and R. palustris, and R. virginiana from R. palustris. Although the multivariate approach was not able to differentiate species when all individuals were considered together, a classification tree showed that it is indeed feasible to identify species in the complex without prior knowledge of the ploidy level of individuals.

Plastid (trnL intron and trnL-F spacer) and nuclear (ITS-1 and ITS-2 rDNA) regions were analyzed to infer the phylogeny and evaluate the classification of Rutaceae subfamilies Rutoideae and Toddalioideae. The inferred phylogeny lends support to merging these two subfamilies established by Engler based on different fruit types. Moreover, Phellodendron, Tetradium, Toddalia, and Zanthoxylum were resolved as a clade, supporting the proposal for a ‘proto-Rutaceae’ group. The molecular data also showed that members of Euodia sensu lato should be placed in three different genera: Tetradium, Euodia, and Melicope. The latter two genera are more closely related to Acronychia than they are to Tetradium. Except for the discrepancy in the position of Melicope vitiflora, the cladistic results are congruent with the morphological and biochemical interpretations made by two previous authors.

The Diosmeae are typical members of the Cape flora. Although the species-level taxonomy has recently received much attention, the generic limits have remained uncertain. In this study plastid DNA (psbA-trnH, atpB-rbcL, and rpl16) were sampled from across the morphological spectrum of species and analysed using parsimony and Bayesian inference. The combined results show Diosmeae to be monophyletic and a number of genera to be polyphyletic. These data are mostly incongruent with the morphology data and suggest that, together with broader sampling of molecular data, more careful examination of morphological characters is needed prior to the adjustment of generic circumscriptions.

Gonolobus foetidus species from southern South America is transferred to Matelea, being characterized by its horizontal pollinia and anthers lacking dorsal appendages (Matelea foetida). A new species, Matelea calchaquina, from arid environments of northwestern Argentina is described and illustrated; data on its habitat, distribution, and phenology is provided. This is a distinctive species within Matelea due to its white flowers with narrow, tubular corollas, which suggest pollination by nocturnal moths. The difficulties in delimiting genera of Gonolobinae based on floral characters are discussed. A key to the species of Matelea from Argentina is included.

Two new species of Matelea (Apocynaceae: Asclepiadoideae, Gonolobinae) are described from northern South America: M. fontana and M. pacifica. The species belong to the Ibatia-Matelea complex, but exhibit distinct differences in floral characters from previously known taxa, including the structure of gynostegial coronas. A key and descriptions to members of the northern South American and West Indian Ibatia-Matelea complex is provided, including M. cumanensis, M. maritima, and M. rubra. Asclepias maritima, Cynanchum fimbriatum, and Ibatia muricata are lectotypified.

Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal position, because its protologue was apparently based on two distantly related species, Rhopalobrachium fragrans and Rhopalobrachium congestum. Despite its new circumscription as a monotypic genus (Rhopalobrachium fragrans) the tribal placement of Rhopalobrachium remained unknown. We investigated, for Rhopalobrachium fragrans, all morphological characters currently used for circumscribing tribes in the subfamily Ixoroideae sensu lato. The species has axillary inflorescences, with valvate flower aestivation, drupaceous fruits with a single pendulous ovule per locule, and 3-pororate pollen grains. We also performed Bayesian and parsimony analyses based on two chloroplast markers, rps16 intron and trnT-F region, to assess the phylogenetic position of Rhopalobrachium within Ixoroideae sensu lato. These analyses produced well-resolved and strongly supported topologies. The results of both the morphological survey and phylogenetic analyses indicated a position of Rhopalobrachium fragrans in the tribe Vanguerieae and a close relationship with the Pacific genus Cyclophyllum.

The enigmatic genus Rhopalobrachium from New Caledonia is proposed as a synonym of the Pacific genus Cyclophyllum, in the tribe Vanguerieae. Recent fieldwork has resulted in new material and field observations that were used in conjunction with herbarium material to examine the morphology and ecology of Rhopalobrachium fragrans. Based on these data, a new combination, Cyclophyllum fragans, was proposed. A lectotype was chosen and a species description and a bibliographic review are included. Following the IUCN criteria, Cyclophyllum fragrans is considered endangered.

Sequences from the internal transcribed spacer region of nuclear DNA (ITS) and the trnL-F regions of chloroplast DNA for fifteen species of Chirita and seven species of Chiritopsis were used to assess phylogenetic relationships between Chiritopsis and Chirita section Gibbosaccus. Parsimony and Bayesian inference (BI) analyses were conducted using separate nuclear and chloroplast data sets, as well as a combined data set. Phylogenetic trees resulting from separate analyses proved highly congruent and the combined analysis of the two data sets produced a well-supported topology of the species and sections examined. Section Gibbosaccus proved paraphyletic and Chiritopsis polyphyletic in all analyses. Our results provide evidence that the species of Chiritopsis are embedded in section Gibbosaccus and were derived at least twice from within section Gibbosaccus. Finally, we reconsider the morphological evolution and adaptation between and within the two genera. The present analyses indicate that nomenclatural changes will be needed to reflect more accurately relationships in the Gibbosaccus-Chiritopsis complex. Only about 10% of the species in Chirita have been sampled and further data are required before any taxonomic changes can be suggested.

Within the parasitic genus Cuscuta, three subgenera have been recognized based on characters of the styles and stigmas. Cuscuta subgenus Cuscuta, with free styles and conical to elongated stigmas, is the most diversified in the Old World with about 25 species. We present the first phylogenetic study of the subgenus using nuclear ITS rDNA and chloroplast trnL intron sequences. Sequences of almost all species of the subgenus were obtained and several individuals of particular taxonomic difficulty or wide geographical distribution were sampled. Both maximum parsimony and Bayesian analyses were performed to evaluate the monophyly of the sections previously accepted in Yuncker's monograph and to investigate phylogenetic relationships between the species. The monophyly of the subgenus could not be tested with our sampling but using three species of subgenus Monogyna as outgroup, the South African section Pachystigma was sister to the remaining species of subgenus Cuscuta. Section Epistigma plus C. capitata are resolved as monophyletic in all analyses. The distinctive C. babylonica was sister to that clade on the ITS trees but it was not resolved on the trnL trees. Two monophyletic groups within section Cuscuta, first identified here, included the species of tropical African distribution in one case and C. europaea, C. approximata, and C. balansae in the other. Factors influencing the taxonomic difficulty of many species in the subgenus include lack of morphological characters, parallelism and gene flow between closely and not so closely related species. Evidence of reticulation events or within species recombination were obtained by both polyphyletic intra-individual ITS sequences and conflicting topologies of the nuclear and plastid trees.

DNA sequences from five chloroplast DNA regions (the rpl16 and rps16 introns and the psbA–trnH, ycf4–cemA, and trnT–L spacers), and the nuclear ribosomal internal and external transcribed spacer (ITS and ETS) regions, were analyzed using maximum parsimony and Bayesian methods to explore the putatively complicated history of the mainly North American genus Arnica. The chloroplast regions were found to contain minimal variation in Arnica. Of 3710 nucleotides, only 119 were variable and 45 informative. However, combined with the ribosomal DNA data, the analysis yielded a number of well-supported clades. Strong support for the monophyly of Arnica was found in both the separate and combined analyses but none of the five currently recognized subgenera was resolved as monophyletic in any of the analyses. Arnica (Whitneya) dealbata and A. mallotopus (Mallotopus japonicus), two species that were previously placed outside Arnica, were confidently confirmed as members of the genus. The analyses revealed that A. nevadensis (subg. Austromontana) is most closely related to A. dealbata and that A. mallotopus forms a strongly supported clade with A. unalaschcensis (subg. Andropurpurea). Earlier biogeographical hypotheses that suggested an arctic origin and southward spread of the genus are not supported by our analyses. Hybridization, homoplasy, and rapid evolution are possible explanations for conflicts between the chloroplast and nuclear ribosomal data sets and for low support of the deeper nodes.