Isozyme Number In Subtribe Oncidiinae (Orchidaceae): An Evaluation Of Polyploidy

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141405/1/ajb208815.pd

Preface to “Linear sequence, classification, synonymy, and bibliography of vascular plants: Lycophytes, ferns, gymnosperms and angiosperms”

Peer reviewe

Molecular Studies of Subfamily Gilliesioideae (Alliaceae)

We present an analysis of relationships in Gilliesioideae (Alliaceae) based on a combined matrix of plastid rbcL, the trnL intron, the trnL-F intergenic spacer, and the rps16 intron and nuclear ITS ribosomal DNA sequences. The results are generally congruent with previous analyses, indicating two well-supported groups: Ipheion plus allied genera ( lpheieae ined.) and Gilliesieae. They also provide higher bootstrap support for many patterns of relationships. Polyphyly of lpheion and Nothoscordum is confirmed. Increased taxon sampling (particularly in Gilliesieae) and additional molecular data would be desirable to provide further resolution and to allow an appropriate taxonomic revision to be made

A Molecular Phylogenetic Study of Generic and Subgeneric Relationships in the Southwest Australian Endemics Conostylis and Blancoa (Haemodoraceae)

We sequenced the plastid gene matK and the nuclear ribosomal spacer ITS for 39 of the 47+ species of Conostylis as well as its monotypic sister genus Blancoa, which some authors have included within Conostylis. Conostylis received 99% bootstrap support as monophyletic, with 100% support that Blancoa is its sister. Within Conostylis, the study provides strong support for two large sister clades, which we refer to as clades A (100%) and B (99%). Clade A consists of C. subgen. Conostylis plus the recently discovered C. glabra of C. subgen. Pendula sect. Divaricata (100%), and C. subgen. Pendula sect. Appendicula (100%). Clade B consists of species mostly placed within the remainder of C. subgen. Pendula but also contains members of the other small subgenera. Subgenus Pendula can be recircumscribed as monophyletic by excluding sect. Appendicula, Conostylis phathyrantha, and C. glabra and including subgen. Androstemma and subgen. Greenia. The status of the other two minor subgenera—C. subgen. Brachycaulon and C. subgen. Bicolorata—requires further investigation. Conostylis sect. Divaricata is polyphyletic. Ancient vicariance events are postulated for Conostylis involving separation of major clades in the northern and southern kwongan regions of southwestern Australia. The phylogenetic pattern in Conostylis is consistent across several lineages with the prolonged persistence of relictual taxa combined with explosive more recent speciation, the latter pronounced in the northern kwongan. There is evidence of significant divergence in major speciation mechanisms and chromosome number change among the three most species-rich subgenera/sections (dysploidy in Pendula and Appendicula vs. diploid speciation in Conostylis). Further investigation is needed to evaluate these ideas and elucidate the patterns of speciation in this most diverse genus of Haemodoraceae

In and out of Madagascar : dispersal to peripheral islands, insular speciation and diversification of Indian Ocean daisy trees (Psiadia, Asteraceae)

This study was supported by the European Union’s HOTSPOTS Training Network (MEST-2005-020561)Madagascar is surrounded by archipelagos varying widely in origin, age and structure. Although small and geologically young, these archipelagos have accumulated disproportionate numbers of unique lineages in comparison to Madagascar, highlighting the role of waif-dispersal and rapid in situ diversification processes in generating endemic biodiversity. We reconstruct the evolutionary and biogeographical history of the genus Psiadia (Asteraceae), a plant genus with near equal numbers of species in Madagascar and surrounding islands. Analyzing patterns and processes of diversification, we explain species accumulation on peripheral islands and aim to offer new insights on the origin and potential causes for diversification in the Madagascar and Indian Ocean Islands biodiversity hotspot. Our results provide support for an African origin of the group, with strong support for non-monophyly. Colonization of the Mascarenes took place by two evolutionary distinct lineages from Madagascar, via two independent dispersal events, each unique for their spatial and temporal properties. Significant shifts in diversification rate followed regional expansion, resulting in co-occurring and phenotypically convergent species on high-elevation volcanic slopes. Like other endemic island lineages, Psiadia have been highly successful in dispersing to and radiating on isolated oceanic islands, typified by high habitat diversity and dynamic ecosystems fuelled by continued geological activity. Results stress the important biogeographical role for Rodrigues in serving as an outlying stepping stone from which regional colonization took place. We discuss how isolated volcanic islands contribute to regional diversity by generating substantial numbers of endemic species on short temporal scales. Factors pertaining to the mode and tempo of archipelago formation and its geographical isolation strongly govern evolutionary pathways available for species diversification, and the potential for successful diversification of dispersed lineages, therefore, appears highly dependent on the timing of arrival, as habitat and resource properties change dramatically over the course of oceanic island evolution.Publisher PDFPeer reviewe

Molecular systematics of Malpighiaceae: evidence from plastid rbcL and matK sequences

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141234/1/ajb21847.pd

Systematics of Xanthorrhoeaceae Sensu Lato, with an Emphasis on Bulbine

We provide here results of a combined analysis of plastid genes rbcL, matK, and ndhF for Xanthorrhoeaceae s.l., the Asphodelaceae/Xanthorrhoeaceae/Hemerocallidaceae clade, which are well supported by the DNA data. Xanthorrhoea (often treated as the sole member of Xanthorrhoeaceae) is sister to the hemerocallid clade (former Hemerocallidaceae); and the asphodelid clade (formerly Asphodelaceae) is sister to them both. For additional species of Bulbine and Jodrellia (both Asphodeloideae), we also collected rps16 intron and ITS nuclear ribosomal DNA sequences to better assess their relationships. Bulbine, with Jodrellia, embedded are sister to the collective genera of subfamily Alooideae in which all species are characterized by strongly bimodal and nearly identical karyotypes, whereas that of Bulbine is much more variable. Cytological studies have previously shown Bulbine to possess a range of karyotypes from graduated to clearly bimodal (although never exactly like the aloid genera) and point toward a lower level of bimodality in the Australian members, all of which are autotetraploid, than in the African members, all of which are diploid. Therefore, there have been two events of particular interest within Bulbine, a change in ploidy and a long-range dispersal event

Molecular phylogenetics of Limonium and related genera (Plumbaginaceae): biogeographical and systematic implications

Phylogenetic relationships within Limonium (Plumbaginaceae) are evaluated using sequence data from three plastid regions (rbcL, the trnL intron, and the trnL-trnF intergenic spacer). Sixty-six species representing the major genera of Staticoideae, including representatives of all sections and genera formerly included in Limonium, have been analyzed using four species of Plumbaginoideae as an outgroup. Analyses of each separate and combined data set yield similar results. Afrolimon is embedded in Limonium and related to L. vulgare, the type of Limonium. Limonium is split into two major clades corresponding to subgenera, but otherwise the current infrageneric classification proved to be artificial. Some groups restricted to particular areas can be recognized, and their synapomorphies are discussed. The presence of an isolated taxon in the Canary Islands is used as a calibration point for age estimates of the major events in the genus, including migrations to the Southern Hemisphere, the Canary Islands, and Asia. The rapid radiation of Limonium in the Mediterranean basin appears to coincide with the desiccation of the Mediterranean Sea in the Messinian (late Miocene).Funding for this project was provided by the Royal Botanic Gardens, Kew, and Consellería de Educación y Ciencia (Comunidad Valenciana, Spain)