Changes to the International Code of Botanical Nomenclature are decided on every six years at Nomenclature Sections associated with International Botanical Congresses (IBC). The XVIII IBC was held in Melbourne, Australia; the Nomenclature Section met on 18–22 July 2011 and its decisions were accepted by the Congress at its plenary session on 30 July Several important changes were made to the Code as a result of this meeting that will affect publication of new names. Two of these changes will come into effect on 1 January 2012, some months before the Melbourne Code is published. Electronic material published online in Portable Document Format (PDF) with an International Standard Serial Number (ISSN) or an International Standard Book Number (ISBN) will constitute effective publication, and the requirement for a Latin description or diagnosis for names of new taxa will be changed to a requirement for a description or diagnosis in either Latin or English. In addition, effective from 1 January 2013, new names of organisms treated as fungi must, in order to be validly published, include in the protologue (everything associated with a name at its valid publication) the citation of an identifier issued by a recognized repository (such as MycoBank). Draft text of the new articles dealing with electronic publication is provided and best practice is outlined. To encourage dissemination of the changes made to the International Code of Nomenclature for algae, fungi, and plants, this article will be published in Brittonia, Botanical Journal of the Linnean Society, BMC Evolutionary Biology, Cladistics, Mycotaxon, MycoKeys, New Phytologist, North American Fungi, Novon, Opuscula Philolichenum, PhytoKeys, Phytoneuron, Phytotaxa, Plant Diversity and Resources, Systematic Botany, and Taxon.

Taxithelium, a moss genus traditionally associated with Sematophyllaceae and characterized by the presence of multiple papillae over the cell lumina, is revised with a worldwide perspective. Taxithelium subgenus Taxithelium comprises eight species. Endemic species include one each from Brazil, Africa, and South America, four from southeast Asia, and one species that occurs in both Africa and South America. Typifications, keys, descriptions, and illustrations are provided.

Osmunda subgenus Osmunda is variable across its worldwide range. In addition to the three species assigned to the subgenus, there is an enigmatic group of plants in Laos and Myanmar. To reveal the taxonomic and evolutionary status of these plants, we performed taxonomic, cytological, and flow-cytometric analyses, and molecular phylogenetic analyses for 32 samples of subgenus Osmunda for three nuclear DNA markers and the chloroplast rbcL gene. Results show that the enigmatic plants are a tetraploid (n = 44, 2n = 88) of hybrid origin from Osmunda regalis and O. japonica, which is described as Osmunda hybrida sp. nov. This is the first record of a naturally occurring polyploid species in the most primitive leptosporangiate family Osmundaceae, previously thought to be diploid throughout. Molecular data suggest that Indian O. regalis is a putative maternal ancestor and O. japonica is a paternal ancestor. Osmunda hybrida shares the fully dimorphic or partially dimorphic leaves with its parental species. Osmunda hybrida presumably originated by interspecific hybridization and polyploidization when the parental species overlapped or less likely via long-distance gametophyte interaction following spore dispersal.

The clover fern Marsilea azorica was described in 1983 from the isolated Azores archipelago in the northern Atlantic, where it is restricted to a single roadside pond. Thought to be an extremely local endemic, it was subsequently listed as a conservation priority species for the Azores, Macaronesia, and Europe, included as ‘critically endangered’ on the IUCN red list, and as ‘strictly protected’ species by the Bern convention and the European Union's habitats directive. However, we present morphological and molecular data (rbcL gene, rps4 gene, rps4-trnS spacer and trnL-trnF spacer sequences), which demonstrate that M. azorica is conspecific with M. hirsuta, a species native to Australia, but widely cultivated and locally invasive in the southern U. S. A. Based on our DNA data, we conclude that these plants are most likely a recent introduction to the Azores from Florida. We recommend removal of Azorean Marsilea from conservation priority lists. While there is no evidence that the small existing population threatens native species, further spread in the Azores should be prevented.

A new fern species, Polystichum fengshanense, is described and illustrated from nine karst caves in northern Guangxi, China. It is a member of Polystichum sect. Haplopolystichum (Dryopteridaceae). A phylogenetic analysis based on chloroplast trnL-F sequences suggests that the new species is most closely related to P. cavernicola, P. minutissimum, and P. speluncicola, species described from karst caves in adjacent southern Guizhou. Morphologically, P. fengshanense can be easily distinguished from these three species by having narrow-type microscales on the abaxial laminar surface, sessile pinnae, and sori closer to the midrib. Palynologically P. fengshanense has granulate perispore sculpturing, whereas P. cavernicola has verrucate perispore sculpturing and P. speluncicola has cristate perispore sculpturing with numerous spinules. Polystichum fengshanense is considered to be critically endangered (CR) based on IUCN red list criteria because of its restricted distribution.

Pleopeltis polypodioides is a widespread Neotropical epiphytic fern consisting of six varieties and one subspecies. Objectives of this study were to assess placement of Polypodium polypodioides within the genus Pleopeltis, the monophyly of Pl. polypodioides, and the relationships and geographic patterns among its infraspecific taxa. Two plastid DNA regions (trnL_UAA-trnF_GAA and psbA-trnH_GUG) were sequenced for individuals across Pl. polypodioides geographic range. Maximum parsimony, maximum likelihood, and network analysis of cpDNA sequences were performed revealing evidence for seven haplotype lineages. The seven lineages, based on sister relationships, can be reduced to four clades within the Pleopeltis polypodioides complex, each of which have distinctive geographic ranges. Clade 1 (Pl. p. vars. burchellii and polypodioides) was found primarily in South America and the Caribbean basin. Clade 2 (Pl. p. subsp. ecklonii) is restricted to southern Africa. Clade 3 (Pl. p. vars. knoblochianum and acicularis) was found only in the north and western regions of Mexico. Clade 4 (Pl. p. vars. acicularis and michauxiana) extends from northeastern and southern Mexico into the U. S. A. and the northern Bahaman Archipelago. Analyses of the data did not fully support the monophyly of Pl. polypodioides; however the majority of the recovered clades correspond to currently defined taxa. Our analyses is of special interest in that it takes a population level approach to a molecular phylogenetic study and provides clarity to a taxonomic group that has proved difficult to elucidate. The results have added to a growing body of evidence that suggests Pl. polypodioides may consist of more than one species.

Scanning electron microscopy has allowed the characterization of cell pattern and ornamentation of the bulb coat, leaf, and seed coat, thereby improving and providing consistency to the taxonomy of Allium. However, the pollination biology and taxonomic understanding of Allium is far from complete, in part because floral structures have been investigated in detail for only a few species. Accordingly, this study provides a description and micro- and macromophological comparative analysis of floral characteristics (including the adjacent bulbils of A. geyeri var. tenerum) of four New World Allium species (A. cernuum, A. geyeri var. tenerum, A. stellatum, and A. textile). Observations of fresh material demonstrated that A. geyeri var. tenerum is distinguished from the closely related A. textile by a larger perianth with elliptical tepals (as opposed to ovate to oblong), filaments slightly shorter than tepals (as opposed to 2/3 as long as tepals), and globose young inflorescences (as opposed to ellipsoid). Ridged cuticles from a variety of floral parts have often been reported in Allium as the main type of epidermal cell covering; results from this study indicate that shape and distribution of cuticles are of systematic significance in conjunction with location of the septal nectary opening, development of ovarian processes, and shape of anther apexes. The presence of ovarian processes is considered a recently derived character; we hypothesize that these structures function as non-secretory visual attractants to pollinators, and in concert with broader inner filaments and clearly concave inner tepals may also represent a special adaptation to facilitate retention of abundant nectar secreted in nodding flowers of A. cernuum and in widely spreading flowers of A. stellatum.

A recent phylogenetic study based on molecular data indicates that Licuala (Arecaceae: Palmae) is not monophyletic. A highly supported group of species is resolved separately from Licuala and the rest of the Livistoninae, and is closely related to Johannesteijsmannia, requiring that the segregate group be placed in a new genus. In this study a phylogeny based on seven gene regions resolves highly supported generic relationships of the Livistoninae. A survey of Licuala specimens from several herbaria indicates that, based on morphology, eight species should be recognized within this genus. A complete description of the new genus, Lanonia, is given. A review of morphology distinguishes synapomorphies in leaf morphology and dioecy of Lanonia species. All eight species are described with complete synonymy, their distributions are mapped, and lists of specimens examined are given. One species occurs in Hainan, one in Java, and six are endemic or nearly endemic to Vietnam. The following new combinations are made: L. acaulis, L. calciphila, L. centralis, L. dasyantha, L. gracilis, L. hainanensis, L. hexasepala, and L. magalonii.

A new species of Merostachys from the Bolivian Yungas, Merostachys yungasensis, is described and illustrated. Merostachys yungasensis is compared to other taxa distributed in Argentina, Bolivia, Paraguay, and Peru, in a table based on morphological characters. Additional micromorphological characters of foliage leaf blade and cauline epidermis are included. In Argentina two species are confirmed: M. claussenii and M. multiramea; the latter species constitutes a new report for this country and is excluded from Paraguay. The specific epithet of M. claussenii is emended, and a lectotype is here designated. Two new synonyms are recognized for M. claussenii and its presence is confirmed from Paraguay after an analysis of previous reports based on misidentifications. The taxa are illustrated. A key for the identification of the species, based on vegetative and reproductive characters, is also provided.

Clematis, a largely temperate genus of vines and lianas, consists of approximately 300 species. Based on a sampling of about 75 species, sequences of the nrITS, the plastid atpB—rbcL spacer, psbA—trnH—trnQ spacer, and rpoB—trnC spacer regions were analyzed using parsimony, maximum likelihood, and Bayesian inference methods. Analyses of the combined data set by the three methods yielded similar topologies. Previously recognized genera including Archiclematis and Naravelia are nested within Clematis, supporting the merging of these genera within Clematis. Ten major clades with various levels of support were detected in the combined analyses. Our results in general do not support previous infrageneric classifications based on morphological characters and suggest significant convergence in floral and vegetative characters in Clematis. Several clades were resolved as regional geographic groups. Bayesian dating suggests a relatively ancient origin of the genus in the Oligocene, yet a relatively recent species radiation of the crown Clematis in the Miocene. Geologic and climatic changes in the late Tertiary to Quaternary are perhaps important for the speciation of Clematis, especially in eastern Asia. Long-distance dispersal of the fruits by wind, water, and/or animals and strong environmental adaptability, are proposed as the main mechanisms for the current cosmopolitan distribution and high species diversity of Clematis.

Maytenus s. l. (including Gymnosporia) is a morphologically diverse genus of about 300 species that is widely distributed in the tropics and subtropics of both the Old and New Worlds. Its delimitation has been extensively debated and despite the segregation of Gymnosporia, Maytenus s. s. remains a heterogeneous, polyphyletic group. To delimit natural segregate genera we increased taxon sampling and generated sequences from two nuclear gene regions (ITS and 26S rDNA) and two plastid loci (matK and trnL-F) to analyze together with morphological characters. Both Moya and Tricerma were found to be nested within the New World Maytenus and are recognized as synonyms of Maytenus s. s.. In contrast, the three New World species of Gymnosporia are recognized as a new genus that is closely related to Gyminda. Haydenia is erected for these three species: H. gentryi, H. haberiana, and H. urbaniana. One or more previously proposed or novel genera are required to accommodate the systematically difficult African Maytenus. Putterlickia, and most likely Gloveria, are nested within Gymnosporia and should be synonymized with that genus. New binomials are required for four Chinese and one Rapan species of Gymnosporia that have been previously treated only as Maytenus: Gymnosporia austroyunnanensis, G. confertiflora, G. dongfangensis, G. guangxiensis, and G. pertinax. Austral-Pacific Maytenus are transferred to Denhamia, requiring eight new binomials: Denhamia bilocularis, D. cunninghamii, D. cupularis, D. disperma, D. fasciculiflora, D. ferdinandii, D. fournieri, and D. silvestris. Existing intrageneric classifications of Gymnosporia and Maytenus s. s. were not supported in their entirety. Gymnosporia is inferred to have had an African origin followed by dispersals to Madagascar, southeast Asia and the Austral-Pacific.

Phyllanthus kidna , the only tree species of Phyllanthus from Cameroon, is described and analysed. Its combination of bilocular berries and two connate stamens indicate no clear affiliation with any known species or infrageneric group within Phyllanthus. Molecular phylogenetic analyses place it as sister to the Indian and East African species Phyllanthus pinnatus and it is also closely related to the New World species of P. acidus and P. chacoensis. Only five individuals are currently known and the species is assessed as critically endangered. The proposed Mefou National Park near Yaounde could save this species from extinction.

Protium section Papilloprotium and Protium alvarezianum are described and a key to the four species of the section provided. The section is distinguished principally by its papillate abaxial leaflet surface, and the petals saccate at base and villous adaxially. The rather widespread edaphic generalist P. ferrugineum shares a common ancestor with two small clades, one containing two white-sand specialists (P. reticulatum and P. alvarezianum) that appear to have diverged from a common ancestor allopatrically via fragmentation of white-sand habitats, and the other exhibiting degrees of edaphic specialization among variants of P. subserratum. This scenario highlights the role of edaphic heterogeneity as a driver in the diversification of the Amazon flora.

Cardiospermum bahianum, a new species from Bahia, Brazil, is described, illustrated, and compared to its putative closest relatives C. anomalum and C. cuchujaquense. The new species is endemic to the caatinga vegetation. In addition, micromorphological characters of leaf epidermis, seed coat, and pollen grains are described. A somatic chromosome number of 2n = 36 is reported. Detailed light and scanning electron microscope photographs of the main characters are presented. The new species belongs to Cardiospermum section Carphospermum. It is distinguished from the similar C. anomalum by its conspicuous lenticels, seeds nearly spherical, and it differs in chromosome number. Additionally, new synonymies for C. anomalum are established. A key to the species of Cardiospermum in Brazil is provided.

Descurainia is a genus in the Brassicaceae distributed throughout portions of the temperate Old and New World. The genus is most diverse in western North America and western South America, with a smaller center of distribution in the Canary Islands and three additional Old World species. Descurainia is well known for its taxonomic complexity, especially within New World species, on account of its numerous intergrading forms coupled with circumscriptions dependent upon inconsistent and overlapping characters. A molecular-based analysis of Descurainia was conducted using DNA sequences from nuclear ribosomal ITS and non-coding cpDNA regions. Descurainia and related genera form the monophyletic tribe Descurainieae, which is divided into two lineages: 1) Hornungia and Tropidocarpum and 2) Descurainia (including Hugueninia), Ianhedgea, and Robeschia. The genus is strongly-supported as monophyletic, and appears to be of Old World origin with recent diversification within the Canary Islands and the New World. Within the New World, three major well-supported lineages can be identified, with South American taxa distributed into four clades that correlate well with fruit dehiscence and orientation. A phylogeny recovered from combined ITS and cpDNA data is not well-resolved with respect to relationships between some major New World lineages, but suggests that multiple independent dispersals of Descurainia have taken place between North and South America. Substantial incongruence between ITS and cpDNA phylogenies, as well as the presence of mixed ITS sequences, point to a complex evolutionary history involving extensive gene flow and hybridization for North American Descurainia.

Many collectors avoid collecting cacti (Cactaceae) and other succulent plants because they are unsure of how to preserve cacti as herbarium specimens. However, preserved specimens of cacti are valuable and crucial for research and conservation. This paper addresses techniques for collection and processing of cacti to make herbarium specimens, with particular reference to the use of ethanol to aid drying.

Previous phylogenetic studies based on DNA sequence data from the genic regions ndhF, matK, atpB—rbcL (cpDNA) and ITS 2 (nrDNA) strongly support the monophyly of the wintergreen group (Ericaceae: Gaultherieae: Diplycosia, Gaultheria, Tepuia) and have assessed the relationships of its major clades. Other studies that include additional genic regions have been limited to two clades corresponding to various sections or series within Gaultheria. Here we expand both the number of species (from 42 to 104) and genic regions (chloroplast matK, ndhF, rpl16, trnL—trnF, trnS—trnG, and the complete ITS region) to further assess phylogenetic relationships in the wintergreen group. With the additional data we detected several areas of incongruence between the trees from the nuclear and combined chloroplast analyses, including a topologically deep conflict involving G. procumbens. Such incongruence likely originated from reticulation events, long considered to have influenced the evolution of various lineages in Gaultheria. We also detected a duplication, possibly nuclear-encoded, of the matK region in one of the Australian/New Zealand lineages. A combined six-gene analysis, in which taxa involved in the conflicting topologies were excluded, yielded higher support values for several early-diverging clades. The monophyly of both Diplycosia and Tepuia is corroborated, as is the successive nesting of Tepuia, G. section Hispidulae (both placements of which have newfound strong support), G. ser. Gymnobotrys, and Diplycosia. Whereas several sections or series with more than one species in the most recent classification of Gaultheria are supported as circumscribed (i.e. G. section Amblyandra and series Hispidulae, Myrtilloideae, and Trichophyllae), others comprise species from two to several different clades.

This paper provides descriptions and illustrations of two new species of Pouteria from the Atlantic forest of Bahia, Brazil (P. atlantica and P. trifida). In addition, distribution maps and a table with main characters to distinguish the new species from related taxa are also included. Pouteria atlantica is characterized by large trichomes that cover the corolla lobes, anther's outer surface, and form tufts on the apex of anthers. Pouteria trifida is distinguished by its long petioles and trifid staminodes. Due to intense deforestation in the Atlantic forest, preliminary IUCN red list assessments are provided. Pouteria atlantica is proposed in the IUCN status critically endangered (CR), while the data for P. trifida are still insufficient.

Milkweeds (Asclepias s. l., Apocynaceae) are characteristic perennial herbs of grasslands in North America and Africa that have long served as models for studying the evolutionary ecology of plant reproduction and plant defense. Generic circumscription of Asclepias has been long debated with recent workers favoring delimitation on geographic grounds; Asclepias s. s. is limited to the Americas and only segregate genera are recognized for African species. A widely used system introduced by Woodson classifies North American Asclepias into nine subgenera, with the largest subgenus, Asclepias, further divided into eight series. We investigated the phylogeny of Asclepias using three noncoding loci from the plastid genome: rpl16 intron, trnC^GCA—rpoB spacer, and the adjacent trnS^GCU—trnG^uuc spacer and trnG^uuc intron. Parsimony, likelihood, and Bayesian analyses were conducted to evaluate hypotheses of continental and taxonomic monophyly. Hypothesis tests were conducted under the parsimony and likelihood criteria. We found moderate support for the monophyly of American Asclepias s. s. and for all but one representative of African Asclepias s. l. Within the Amerian clade, South American species are strongly supported as monophyletic and derived from North American ancestors. Only one of Woodson's 17 infrageneric taxa was found to be monophyletic. Monophyly of more than one half of the remaining 16 taxa could be statistically rejected using a conservative α level. Our results are consistent with taxonomic restriction of Asclepias to American species and single colonization events from Africa to North America and North America to South America. They also point to a need for major restructuring of infrageneric classification and future revsionary work.

A new species of the Afro-Malagasy genus Phyllopentas Kårehed & B. Bremer, Phyllopentas flava Razafim., T. Andriam. et Kårehed, is described and illustrated. This plant is restricted to the Itremo region in southeastern Madagascar and is distinct morphologically from the other species of the genus by its pubescent, narrowly ovate to narrowly elliptic leaves, grey-whitish and thickly hairy midribs and secondary veins on the lower surfaces of leaves, and functionally dioecious and heterodistylous flowers. Summaries of distribution, phenology, habitat, and ecology are given and a conservation assessment is also provided.

A new Hedythyrsus species from Katanga (D. R. Congo), Hedythyrsus katangensis, is described and illustrated based on classic herbarium taxonomy. The generic placement of the new species was determined by comparing it to African genera of the Hedyotis-Oldenlandia complex of the Spermacoceae s. l. that share the terminal position of the inflorescences and the capsular fruits opening by four valves, i.e. Agathisanthemum, Dibrachionostylus, Hedythyrsus, Mitrasacmopsis, and Pseudonesohedyotis. The new species differs from the known Hedythyrsus species in being geoxylic herbs instead of shrubs, and in having bifid, not multifid, stipules. Within Hedythyrsus katangensis two varieties are recognized. Variety ternifolius is distinguished from the type variety by the position of the leaves (often ternate in var. ternifolius, always opposite in var. katangensis) and the pubescence of stems, ovary, and calyx (scabrous to shortly hairy in var. ternifolius, glabrous in var. katangensis). Following the IUCN red list criteria the species can be classified as near threatened.

Lepechinia (Lamiaceae subf. Nepetoideae) is a New World genus composed of about 42 species distributed primarily from Northern California to Central Argentina. Previous morphological and molecular studies on Lepechinia have raised questions on the monophyly of the genus and its placement within the tribe Mentheae. In this paper the phylogenetic placement and monophyly of Lepechinia is examined within the context of the tribe Mentheae using cpDNA (ycfl and trnL-F) and nrDNA (ITS and ETS) markers. Melissa is shown to be sister to Lepechinia in both cpDNA and nrDNA analyses, and the monotypic genera Chaunostoma and Neoeplingia are found to be embedded within Lepechinia. The subtribe Menthinae is shown to be paraphyletic, with several genera needing to be reassigned. In particular, Neoeplingia should be included within the subtribe Salviinae. The genera Heterolamium and Melissa, both previously unplaced with regard to subtribe, are now clearly assigned to the subtribes Nepetinae and Salviinae, respectively. The cpDNA marker ycfl has great phylogenetic utility, and is shown to be 50% more informative than trnL-F for the taxa used in this study.

Clemdendrum in Borneo is revised and a key to the 23 taxa recognized is presented. Confusion surrounding application of certain names and species circumscriptions is dispelled. Two new combinations, Clerodendrum japonicum var. bethuneanum and Clerodendrum pubiflorum, are made. Clerodendrum sayapense is a new species from Sabah.

Solanum morelliforme is an epiphytic wild potato (Solanum section Petota) species widely distributed throughout central Mexico to Honduras. A strikingly disjunct (approximately 4,000 km) population was recently discovered in Bolivia, representing the first record of this species in South America, and the first species in the section growing in both North and Central America and in South America. Our maximum entropy analysis of 19 climatic variables matches the occurrence of the South American locality with great precision. It demonstrates the strong predictive quality of this procedure and suggests similar localities where this species may be found, especially along the eastern slopes of the Andes in the Yungas region of southern Peru and Bolivia. In addition, the presence of S. morelliforme in South America adds to emerging data from yet other sources to question long-held hypotheses of the origin of section Petota in North and Central America.

Solanum section Herpystichum includes 10 species of ground-trailing and climbing vines that root adventitiously at the nodes. Molecular data support section Herpystichum as a member of the Potato clade of Solanum. All of the species inhabit primary and secondary rainforests and occur from southern Mexico to northern Peru. The group is defined by its vining, node-rooting habit, and by its fruit structure; several species have strongly flattened fruits that are unique in Solanum. Most species of sect. Herpystichum have narrow distributions, and four species are endemic to Ecuador and one is endemic to Colombia. Moreover, they tend to be rare in the habitats where they occur and, as a result, are poorly collected and poorly known. Also, because of their restricted distributions, small numbers of populations, and habitat destruction, seven of the 10 species are considered rare and threatened. Descriptions, distribution maps, a phylogeny, photos or illustrations, and a key to the species are presented.

Analysis of ITS sequence data showed unexpected complexity for Eupatorium album and E. petaloideum, a closely related species pair from eastern North America that has been considered to form a single species. The two species consistently differed in ITS sequence by seven to eight bp as well as a one bp indel, and detailed analysis revealed little intraspecific variation. The ITS sequences of other samples that had similar but slightly differing morphology and were pollen sterile gave several patterns involving bp or indel polymorphisms that indicated that they were of hybrid derivation. Based on differences in leaf and phyllary shape and glandular trichome distribution it was possible to delimit the individual hybrid combinations from one another and from their progenitor species. Material previously called E. album from the western part of its range is of hybrid origin from E. album and E. lancifolium, and is described here as Eupatorium sullivaniae. Material from the northeastern part of the range previously called E. album var. subvenosum is a hybrid derivative of E. petaloideum and E. hyssopifolium, elevated here to Eupatorium subvenosum. Samples having the general morphology previously associated with E. album var. vaseyi included hybrid derivatives of the combinations E. petaloideum/E. sessilifolium, here reinstated as E. vaseyi, and E. petaloideum/E. sessilifolium/E. perfoliatum, here reinstated as E. fernaldii. Other samples gave ITS sequence data consistent with a derivation from E. album/E. hyssopifolium. The species of hybrid derivation have geographic ranges that extend beyond those of the inferred progenitors, in the case of E. subvenosum involving a disjunction of several hundred kilometers, suggesting that there have been considerable differences in species ranges over time.

The cosmopolitan genus Nymphoides contains approximately 50 species that vary considerably in growth habit, inflorescence architecture, and in vegetative, floral, and seed morphology We undertook a phylogenetic study of 31 Nymphoides species, including all species native to Australia, to evaluate interspecific relationships and to infer the evolution of heterostyly and inflorescence architecture. Phylogenetic analysis of morphological data resolved several clades of species, but with poor branch support. Molecular data from nuclear (ITS) and plastid (matK/trnK) DNA sequences were significantly incongruent regarding the phylogenetic placement of many clades and species. Two major clades were resolved consistently: a clade sister to N. minima and the clade comprising these two lineages. Incongruent phylogenetic placements of several Nymphoides species were attributed to putative ancestral hybridization that produced conflicting phylogenetic signals between the maternally inherited cpDNA and the biparentally inherited nuclear DNA (subsequently homogenized to a single allelic variant by concerted evolution). Ancestral character state reconstruction indicated that the first Nymphoides species were heterostylous, followed by four independent transitions to homostyly and up to four subsequent reversions back to heterostyly. The evolutionary history of dioecy and gynodioecy could not be ascertained with confidence, owing to incomplete taxon sampling, poor resolution of crown clades, and incongruence between nuclear and plastid sequence data. Ancestral state reconstruction also indicated that the expanded inflorescence morphology found in several Australian and tropical Asian Nymphoides species represents the ancestral condition for the genus, from which a condensed morphology (found in most other Nymphoides species worldwide) evolved independently at least twice.

Ivy (Hedera spp., Araliaceae) is a polyploid complex of woody vines. Native to Eurasia and northern Africa, ivy is cultivated worldwide and has become an aggressive invader of North American forests. Despite its ecological impacts and economic significance to the horticultural industry, the taxonomy of Hedera is controversial and historical relationships are poorly defined. Here we characterize the phylogeny of Hedera based on the low-copy nuclear locus Granule-bound starch synthase I (GBSSI) and twelve non-coding cpDNA regions. Maximum parsimony and Bayesian analyses of both data sets identified Hedera as monophyletic. For GBSSI, we isolated eighteen haplotypes that were widely shared across species. There was no evidence of fixed heterozygosity or haplotype additivity in polyploids, suggesting possible autopolyploid origins. For cpDNA, we isolated sixteen haplotypes that were highly structured by geography. Haplotype diversity and phylogenetic structure were greatest in northern Africa and southern Europe. Thus, while most members of the Araliaceae reside in tropical and subtropical Asia, the early diversification of Hedera probably occurred in the Mediterranean Basin. Geographically-structured clades included diploid and polyploid species, suggesting that genome duplication has occurred repeatedly in the genus. Closely-related ivies often differed in leaf size and trichome morphology, indicating evolutionary lability of traits traditionally used for classification. Nonetheless, we recovered similar or identical DNA sequences within morphologically-defined species. Notable exceptions included southern populations of H. helix (H. helix subsp. caucasigena and H. helix subsp. rhizomatifera) that had cpDNA haplotypes distinct from those of central and northern Europe (H. helix subsp. helix).