The neotropical liverwort genus Dicladolejeunea, which has recently been placed in synonymy with Taxilejeunea, is proposed as synonymous with Lejeunea. Dicladolejeunea anomala and D. saccatiloba, as well as Taxilejeunea longiloba, are placed in synonymy with Lejeunea rotundifolia. Oil bodies, androecia, gynoecia, and the sporophyte of L. rotundifolia are described for the first time. Lejeunea rotundifolia is lectotypified.

Nymphaeales (Nymphaeaceae and Cabombaceae) comprise eight genera and approximately 70 species of aquatic plants, with a worldwide distribution in tropical to temperate regions. Previous analyses of molecular and morphological data have provided a well-resolved and strongly supported generic-level phylogeny for the order. Using published nuclear 18S rDNA and plastid rbcL and matK DNA sequences and a published topology for Nymphaeales, we estimated the divergence times of genera in this clade. We applied four different methods, a strict molecular clock, nonparametric rate smoothing (NPRS), penalized likelihood (PL), and a Bayesian method, to estimate divergence times. We calibrated the trees by using the minimum age of the angiosperm crown group constrained to 131.8 mya. Our results indicate that extant Nymphaeales diversified into two major clades corresponding to Cabombaceae and Nymphaeaceae during the Eocene (44.6 ± 7.9 mya); extant genera of Nymphaeaceae date to 41.1 ± 7.7 mya, and extant Cabombaceae diversified during the Miocene (19.9 ± 5.6 mya). Whereas the stem lineage of Nymphaeales is old based on fossil evidence (125–115 mya), our results indicate that extant Nymphaeales diversified relatively recently. In another set of analyses we used PL to estimate the age of the angiosperms using two prominent Nymphaeales fossils as calibration points. These analyses suggest that these “Nymphaeales” fossils may be attached at deeper nodes than proposed in earlier studies. Using dispersal-vicariance analysis, we infer that the ancestor of Nymphaeales occupied the American and Eurasian continents during the Eocene and that the present distributional patterns require several subsequent dispersal and extinction events. This biogeographic inference is supported by the fossil record.

Vegetative shoots and a newly discovered fruit of Ceratophyllum are described from diatomite of the middle Miocene Shanwang Formation in Shandong Province, eastern China. Based on the fruit, the fossil can be referred to C. muricatum subsp. muricatum. The presence of this Ceratophyllum indicates that the climate was slightly warmer and more equable than today.

The Annonaceae are a pantropical angiosperm family, in which Anaxagorea is sister to the rest of the family based on previous phylogenetic studies. Anaxagorea is the only genus of Annonaceae with a disjunct distribution in South and Central America and southeast Asia. Earlier arguments on the biogeographic history of Annonaceae led to the hypothesis of a Laurasian origin for Anaxagorea. A detailed phylogenetic study was conducted using 75 morphological characters and molecular sequences from the atpB-rbcL, psbA-trnH, and trnL-trnF spacer regions and the trnL intron. Molecular analyses alone do not support the monophyly of the Asian species, but the morphological and combined molecular and morphological analyses do. All analyses place most Central American species in a clade, but none support an Asian-Central American clade. South American species form a basal grade, thereby refuting the hypothesis of a Laurasian origin for the genus and indicating instead a Gondwanan origin. Parsimony optimizations and DIVA reconstructions of biogeographic data indicate separate dispersals from South America to Central America and to Asia. Molecular age estimates indicate an Eocene origin for the genus. The clade containing the Asian and Central American species is dated to be younger than the Oligocene climatic deterioration, which reduces support for the North Atlantic land bridge as a dispersal route from South America to Asia.

Following recent phylogenetic studies of the families and genera of Dioscoreales, the identification of monophyletic infrageneric taxa in the pantropical genus Dioscorea is a priority. A phylogenetic analysis based on sequence data from the plastid genes rbcL and matK is presented, using 67 species of Dioscorea and covering all the main Old World and selected New World lineages. The analysis used 14 outgroup taxa, including Trichopus Gaertn., Tacca J.R. & G. Forster, Stenomeris Planch., Burmannia L. and Thismia Griff. The main findings are: a) that a clade of rhizomatous taxa is sister to the rest of Dioscorea; b) the main Old World groups (such as the right-twining D. sect. Enantiophyllum) are monophyletic and c) there are two distinct lineages among the endemic Malagasy taxa. The consequences of the results for infrageneric classification of Dioscorea is considered, in particular the possibility of greatly simplifying the classifications of Knuth and Burkill. The results are also used to present novel hypotheses of character evolution in selected underground storage organ, inflorescence, fruit and seed characters and to discuss the origins of diversity in Dioscorea.

Pollen character evolution in yams (Dioscorea: Dioscoreaceae) was investigated in relation to the phylogeny obtained from a recent combined analysis of rbcL and matK gene sequences. The following characters were evaluated: pollen size, aperture number, sexine ornamentation, perforation density, and orbicule presence or absence. Continuous characters were coded using the gap weighting method. Each character was optimized using MacClade onto a tree selected at random from analyses based on molecular data of Wilkin et al. The results indicate that in Dioscorea pollen size decreases in the more derived clades. The latter observation may be related to the evolution of annually replaced tubers. Aperture number increases from one in the monosulcate Stenophora clade (sister to the rest of Dioscorea) to two in other Dioscorea clades. This may be related to the presence of simultaneous microsporogenesis in Dioscorea. A perforate sexine is plesiomorphic in Dioscorea and a striate pattern has evolved more than once and is particularly characteristic in the Malagasy clade. Sexine ornamentation in the Stenophora clade is diverse. The endemic allotetraploid D. pyrenaica is characterized by large, monosulcate, gemmate pollen. The Dioscorea B clade is characterized by pollen with small, dense perforations. Orbicules occur in all Dioscorea species, but are absent in most of the outgroup taxa.

The Elegia group comprises 60 species of African Restionaceae, a large and ecologically dominant element of the Cape flora of South Africa. The recognition of the group was based upon the shared possession of unbranched fertile culms, the presence of a distinct abscission line at the base of the leaf sheaths, and inserted anthers at anthesis. The taxonomy of the group has been problematic, and every monographer of the group used different generic delimitations. Based upon a cladistic analysis of sequence data from multiple chloroplast regions (trnL-F region, atpB-rbcL spacer, trnK intron, matK, and rbcL) for all 60 species, we seek optimal generic groupings that are monophyletic, conservative nomenclaturally, and readily diagnosable using morphological characters. We found no support for the monophyly of the Elegia group, as the genus Askidiosperma, itself forming a clade of 12 species, was placed outside the group. Within the remaining elements we found no acceptable generic groupings, and consequently propose an expanded circumscription of Elegia that includes the genera Chondropetalum and Dovea, as these latter two genera are embedded within the former. New combinations are E. acockii, E. aggregata, E. decipiens, E. ebracteata, E. hookeriana, E. marlothii, E. microcarpa, E. recta, E. tectorum, and E. macrocarpa.

Haptanthus is known from only a single collection despite several attempts to recollect it. Because of its unique inflorescence and flowers, and the specimen's lack of fruit, the original authors were unable to assign it to an existing family. After 12 years Nelson described it as the type of a new family, Haptanthaceae. The original authors mainly described and illustrated the gross morphology, pistil anatomy, and pollen of Haptanthus. In attempting to assign it to a family, eight familial placements were considered and reasons were given for their rejection. In the present paper additional characters of the leaf, stem, and pistil, mainly anatomical, are described and illustrated. Most of the wood characters are archaic (primitive). Haptanthus has a suite of characters indicating that it is probably wind-pollinated. Consideration of all the characters studied to date, and examination of additional literature and herbarium specimens of several families, enable us to suggest Flacourtiaceae and Euphorbiaceae as the closest relatives of Haptanthaceae. Recently, Flacourtiaceae has been suggested by another author. Key characters of the three families are compared in a table.

Haptanthus hazletii is an enigmatic broad-leaved angiosperm of uncertain affinities. Previous research indicated that the staminate flowers had a morphology unique within the angiosperms, consisting of a single stamen with latrorse dehiscence. Re-examination of the morphology and anatomy of the staminate flowers does not support this interpretation but shows that the two elliptic flattened structures bearing the anthers are atop a solid pedicel-like stalk and are appressed to one another. These structures can be interpreted as either tepals with adnate bilocular introrse stamens or as foliose introrse stamens, either interpretation being unlike conventional floral structures. The anatomy of the flower reveals a siphonostele in the pedicel that divides into two arcuate traces supplying the anther-bearing structures. The vascular bundle runs up between the thecae giving off small branches to them; it terminates towards the apex of the flattened structure. Each theca is surrounded internally by massive tissue with endothecial thickenings. The unusual combination of floral characters does not easily fit into any known group, although the suite of characters indicates that the genus is probably amongst the basal eudicots, perhaps near Buxaceae.

Phylogenetic analyses of DNA sequences of six species of Platanus were conducted to estimate species relationships and analyze biogeographic history. On the basis of a broader analysis of the third exon of the nuclear gene LEAFY, the root node for the genus was confirmed to fall between subg. Castaneophyllum (P. kerrii) and the species of subg. Platanus. Separate phylogenetic analyses of the nuclear ribosomal ITS region, the 3′ region of the second intron of LEAFY, and the chloroplast region trnT-trnL intergenic spacer provided various levels of resolution, and the combined data yielded a fully resolved set of relationships within subg. Platanus. Two major clades were identified: one with species from Europe (EUR) and western North America (WNA) (P. orientalis, P. racemosa s.l.), the other with species from eastern North America (ENA; US and Canada) and eastern Mexico (EMEX) (P. mexicana, P. occidentalis, and P. rzedowskii). Within subg. Platanus, six subclades corresponded to previously recognized taxa, and one accession may be of hybrid origin. The historical biogeography of Platanus was interpreted using phylogenetic pattern, estimates of divergence times, the fossil record, and climate reconstructions. The pattern of relationships was consistent with a hypothesis of vicariance and the oldest divergence between taxa within the set of area relationships of ((WNA EUR), (ENA MEX)) suggested an initial barrier affecting taxa that are now mostly confined to North America. The second oldest divergence within subg. Platanus involves the intercontinental disjunction of semi-arid species from WNA EUR, which diverged by at least 15 MYBP, consistent with the Madrean-Tethyan hypothesis. Calibrated phylogenies were used to estimate divergence times for five more recent intracontinental disjunctions. These times correlated with the timing of geological events in southwestern North America and northern Latin America.

Members of Pereskia exhibit some presumably plesiomorphic characters for the Cactaceae including shrubby habit, non-succulent or partially succulent leaves, and in some species, nearly superior ovaries. In addition, the members show a transition from perigynous flowers with half-inferior ovaries to those species having true receptacular epigyny (the predominant condition in the Cactaceae). To examine interspecific relationships within Pereskia we utilized cpDNA restriction-site data and sequences from two non-coding regions of the plastid genome—the psbA-trnH intergenic spacer and the rpl16 intron. Maximum parsimony and Bayesian analyses identified three major clades: a clade containing the widespread P. aculeata and the Andean species, a clade containing six species found primarily in southeastern Brazil, Paraguay, Uruguay, Argentina, and Bolivia, and a third clade centered in southern Central America and the Caribbean. The relationship between these three clades and the rest of the Cactaceae remains unresolved, but our data do suggest that Pereskia may be paraphyletic. The sister taxon relationship for the yellow flowered species of Pereskia (P. aureiflora, P. guamacho) was also confirmed, despite their widely disjunct distribution.

The North American species of Celtis have been believed on anecdotal grounds to hybridize commonly in nature, and an understanding of the nature and frequency of natural hybridization among species of Celtis is necessary for understanding phylogenetic relationships within the genus. Extensive natural introgression has been strongly suspected between two species with ranges that overlap broadly in Texas, Celtis laevigata and C. reticulata. Statistical study of morphological and AFLP data was undertaken to test the extent and genetic consequences of natural hybridization between them. Results indicate that there is little or no natural hybridization between these species, contradicting past conclusions. The variability and apparent intergradation between the species that led to the hypothesis of introgression are apparently due to high levels of shared ancestral polymorphism at many loci, and exceptionally high levels of position-associated variation in leaf morphology within individual trees.

We examined shapes and surface features of seeds of 19 species of Hawaiian Hedyotideae using scanning electron microscopy. The study concentrates on the Hedyotideae previously recognized in the genus Hedyotis and here recognized as the genus Kadua, lacking diplophragmous capsules, and having salverform, fleshy corollas with appendaged lobes. The seeds fell into four main morphological groups: (1) hat- or fan-shaped, laterally cuneate, compressed seeds (Kadua subg. Kadua and atypical species of Gouldiopsis and Wiegmannia); (2) ovoid or elliptic seeds with conspicuous bubble-shaped bodies included in the areoles (cells) (most of sect. Wiegmannia); (3) flat broadly winged seeds with a lateral hilum attached at wing margin (Kadua centranthoides, type species of sect. Gouldiopsis); (4) brick-like or blocky seeds with a centric ventral hilum (Kadua subg. Gouldia). The results of the seed study correlate with the taxonomic arrangement in the current Hawaiian flora. An appendix lists the Kadua names including necessary new combinations and their Hedyotis synonyms for the Hawaiian taxa and seven additional South Pacific taxa having the same corolla characters. The following new names are published: Kadua subg. Gouldia (A. Gray) W. L. Wagner & Lorence, Kadua sect. Gouldia (A. Gray) W. L. Wagner & Lorence, Kadua fosbergii (W. L. Wagner & D. R. Herbst) W. L. Wagner & Lorence, Kadua axillaris (Wawra) W. L. Wagner & Lorence, Kadua sect. Phyllozygia (W. L. Wagner & Herbst) W. L. Wagner & Lorence, Kadua tryblium (D. R. Herbst & W. L. Wagner) W. L. Wagner & Lorence, Kadua sect. Oceanica (Fosberg) W. L. Wagner & Lorence, Kadua sect. Austrogouldia (Fosberg) W. L. Wagner & Lorence, Kadua lucei (Lorence & J. Florence) W. L. Wagner & Lorence, Kadua nukuhivensis (J. Florence & Lorence) W. L. Wagner & Lorence, Kadua tahuatensis (Lorence & J. Florence) W. L. Wagner & Lorence, Kadua grantii (Fosberg) W. L. Wagner & Lorence, Kadua sect. Protokadua (Fosberg) W. L. Wagner & Lorence, Kadua coriacea (J. E. Smith) W. L. Wagner & Lorence, Kadua sect. Gouldiopsis (Fosberg) W. L. Wagner & Lorence, Kadua foggiana (Fosberg) W. L. Wagner & Lorence, Kadua sect. Wiegmannia (Meyen) W. L. Wagner & Lorence, Kadua cordata Cham & Schltdl. subsp. remyi (Hillebr.) W. L. Wagner & Lorence, Kadua cordata Cham & Schltdl. subsp. waimeae (Wawra) W. L. Wagner & Lorence, Kadua degeneri (Fosberg) W. L. Wagner & Lorence, Kadua degeneri (Fosberg) W. L. Wagner & Lorence subsp. coprosmifolia (Fosberg) W. L. Wagner & Lorence, Kadua elatior (H. Mann) W. L. Wagner & Lorence, Kadua flynnii (W. L. Wagner & Lorence) W. L. Wagner & Lorence, and Kadua st.-johnii (B. C. Stone & Lane) W. L. Wagner & Lorence.

We used DNA sequence data from four regions ([1] nrITS; the chloroplast [2] rps16 intron, [3] trnG-S spacer, and [4] trnL-F intron and spacer) to study phylogenetic relationships within tribe Acantheae (Acanthaceae). Our sample includes 18 of 20 recognized genera and 82 of ca. 500 species (plus two Justicieae as out-groups). Results of parsimony and Bayesian analyses were entirely congruent and provided strong support for monophyly of two sub-lineages of Acantheae, referred to here as the ‘one-lipped corolla’ and ‘two-lipped corolla’ lineages, reflecting notable differences in corolla morphology. Subsequent analyses were of the two sublineages separately in order to include all characters (a hypervariable region of trnG-S could not be aligned across the full range of taxa but could be aligned within sublineages). The ‘one-lipped corolla lineage’ comprises six clades of Old World taxa related as follows: [Crossandra (Sclerochiton clade {Cynarospermum [Blepharis (Acanthus clade Acanthopsis)]})]. All presently recognized genera are strongly supported as monophyletic, except that Blepharis dhofarensis is placed with species of Acanthus, with strong support from both parsimony and Bayesian inference (monophyly of Blepharis was rejected by both parsimony and likelihood). Alternate hypotheses based on calyx and androecial morphology regarding Crossandrella and Streptosiphon could not be rejected, but placement of these genera with some species of Crossandra based on pollen was rejected. The ‘two-lipped corolla lineage’ is strongly supported and includes one clade of Old World plants (the Stenandriopsis clade) that is sister to a strongly supported clade that includes all New World Acantheae as follows: [Stenandrium clade (Neriacanthus {Aphelandra lineage})]. The Aphelandra lineage includes the ‘armed’ Aphelandra clade and a polytomy of six unresolved clades: (1) A. squarrosa, (2) Encephalosphaera clade, (3) Geissomeria clade, (4) A. aurantiaca clade, (5) A. pulcherrima clade, (6) Rhombochlamys. In contrast to patterns in the one-lipped lineage, genera in the two-lipped lineage are mostly not monophyletic nor are relationships among them strongly supported by our molecular data or by morphological synapomorphies. We discuss these results in the context of evidence from other sources including macromorphology, palynology, chromosome numbers, and geographic distribution.

Three new species of Capsicum from eastern coastal Brazil are described and illustrated. Capsicum pereirae from Espírito Santo and Minas Gerais is related to C. flexuosum and C. schottianum. Capsicum friburgense, endemic to a restricted area in Nova Friburgo (Rio de Janeiro state) is similar to C. scolnikianum, C. cardenasii, and C. mirabile. Capsicum hunzikerianum from São Paulo is closely allied to C. cornutum. A key to differentiate the wild Capsicum species from Brazil is provided.

The phylogeny of Brassaiopsis (Araliaceae), a morphologically diverse and widely distributed genus in Asia, was estimated based on sequences of the internal transcribed spacer regions (ITS) and 5S nontranscribed spacer (5S-NTS) of the nuclear ribosomal DNA. Two main paralogous copies of 5S-NTS were found for Brassaiopsis but both were not recovered for all species. All but one species of Brassaiopsis was represented by 5S-NTS (copy 1). Separate parsimony analyses of ITS and 5S-NTS (copy 1) generated largely congruent topologies, but several paralogous 5S-NTS sequences precluded data combination. A sister relationship of Brassaiopsis with Trevesia was strongly inferred. The divergence of Brassaiopsis from Trevesia was estimated to have occurred ca. 20 million years ago (MYA) during a period of mountain building and climatic change in SE Asia. Our analysis suggests a rapid evolutionary radiation of Brassaiopsis in the Sino-Himalayan region and Indochina at ca. 8 MYA. Several clades within the genus were circumscribed based on ITS and 5S-NTS analyses: 1) B. aculeata, B. glomerulata, and B. hainla; 2) B. gigantea, B. grushvitzkyi, B. moumingensis, and B. stellata; 3) B. ciliata and B. hispida; 4) B. fatsioides and B. palmipes; and 5) B. gracilis and B. phanerophlebia. Brassaiopsis producta is morphologically unique in possessing a 3–5-locular ovary, and its phylogenetic position was not well resolved in either analysis. Morphological characters previously considered important for defining species and subgeneric groups were shown to have had multiple origins (e.g., leaf architecture and locule number in the ovary). The Brassaiopsis phylogeny supports strong biogeographic connections between S China and Indochina, S China and SW China, and SW China and the eastern Himalayas.

The federally listed threatened species, Helenium virginicum, is endemic to 30 sinkhole ponds in two counties in Virginia, but a Helenium population in Pomona, Missouri, differs scarcely from H. virginicum from Virginia in morphology, ecology, and non-coding nrDNA ITS sequences. In response to continuing taxonomic uncertainty regarding the Missouri population, we enlarged our ITS comparisons from our previous work to include 48 populations, more than doubling the number of H. virginicum populations, and including populations of H. autumnale and H. flexuosum from 12 states in the United States and two Canadian provinces. Phylogenetic analyses were conducted using Bayesian, maximum-likelihood, and maximum-parsimony methods, and showed strong support for a monophyletic species of all H. virginicum from Virginia, the Pomona population and 29 other recently discovered populations in Missouri. We conclude that H. virginicum is narrowly endemic and disjunct between Virginia and Missouri. Additionally, one population of H. autumnale from the Bruce Peninsula, Canada, was found to be the sister group to H. virginicum. We discuss the impact of Pleistocene and Holocene geoclimatic changes on the phylogeography of these plants, including the possibility that the H. autumnale complex has become more disjunct and narrowly endemic since the Xerothermic Period (8–4Ka).

A new species of Senecio from the Anti Atlas of Morocco, S. kerdousianus (Asteraceae: Senecioneae), is described and illustrated. The new species can be distinguished from other species of Senecio growing in the Anti Atlas in their discoid capitula, subentire lower leaves with coarse sinuate dentate margins, and cauline and upper leaves with broad auriculate bases. A key to related species from SW Morocco, south of the High Atlas, is provided.