36 research outputs found
Taxonomical and distributional notes on Polylepis (Rosaceae)
AbstractPolylepis pacensis M. Kessler & Schmidt-Leb. spec. nov. is described; P. flavipila (Bitter) M. Kessler & Schmidt-Leb., P. incarum (Bitter) M. Kessler & Schmidt-Leb., P. lanata (Kuntze) M. Kessler & Schmidt-Leb., and P. subtusalbida (Bitter) M. Kessler & Schmidt-Leb. are elevated from subspecies or varietal to species rank; P. triacontandra Bitter is reinstated as a species. The accompanying Electronic Supplement provides an updated key to species in Polylepis, and reports extensions to the known distribution ranges of three additional species of the genus.See also Electronic Supplement at: http://www.senckenberg.de/odes/06-01.ht
Species trees from consensus single nucleotide polymorphism (SNP) data: Testing phylogenetic approaches with simulated and empirical data
Datasets of hundreds or thousands of SNPs (Single Nucleotide Polymorphisms) from multiple individuals per species are increasingly used to study population structure, species delimitation and shallow phylogenetics. The principal software tool to infer species or population trees from SNP data is currently the BEAST template SNAPP which uses a Bayesian coalescent analysis. However, it is computationally extremely demanding and tolerates only small amounts of missing data. We used simulated and empirical SNPs from plants (Australian Craspedia, Asteraceae, and Pelargonium, Geraniaceae) to compare species trees produced (1) by SNAPP, (2) using SVD quartets, and (3) using Bayesian and parsimony analysis with several different approaches to summarising data from multiple samples into one set of traits per species. Our aims were to explore the impact of tree topology and missing data on the results, and to test which data summarising and analyses approaches would best approximate the results obtained from SNAPP for empirical data. SVD quartets retrieved the correct topology from simulated data, as did SNAPP except in the case of a very unbalanced phylogeny. Both methods failed to retrieve the correct topology when large amounts of data were missing. Bayesian analysis of species level summary data scoring the two alleles of each SNP as independent characters and parsimony analysis of data scoring each SNP as one character produced trees with branch length distributions closest to the true trees on which SNPs were simulated. For empirical data, Bayesian inference and Dollo parsimony analysis of data scored allele-wise produced phylogenies most congruent with the results of SNAPP. In the case of study groups divergent enough for missing data to be phylogenetically informative (because of additional mutations preventing amplification of genomic fragments or bioinformatic establishment of homology), scoring of SNP data as a presence/absence matrix irrespective of allele content might be an additional option. As this depends on sampling across species being reasonably even and a random distribution of non-informative instances of missing data, however, further exploration of this approach is needed. Properly chosen data summary approaches to inferring species trees from SNP data may represent a potential alternative to currently available individual-level coalescent analyses especially for quick data exploration and when dealing with computationally demanding or patchy datasets.This study was partly supported by a Centre of Biodiversity Analysis Ignition Grant to A.N.S.-L. and Justin Borevitz in 2013/14
There's gold in them thar hills! Morphology and molecules delimit species in Xerochrysum (Asteraceae; Gnaphalieae) and reveal many new taxa
Golden everlasting paper daisies in the genus Xerochrysum Tzvelev are iconic Australian native plants grown worldwide. The X. bracteatum species complex has been regarded as taxonomically confusing and in need of revision for over 60 years. We applied morphological and molecular analyses to delimit species, detect common ancestry among populations, and identify putative hybrids in the genus Xerochrysum (Asteraceae: Gnaphalieae). Multiple lines of evidence provided strong support for the recognition of new taxa. Here we describe the following 11 new species: X. andrewiae T.L.Collins & J.J.Bruhl, X. berarngutta T.L.Collins & I.Telford, X. copelandii J.J.Bruhl & I.Telford, X. frutescens J.J.Bruhl & I.Telford, X. gudang T.L.Collins & J.J.Bruhl, X. hispidum T.L.Collins & I.Telford, X. macsweeneyorum T.L.Collins, X. murapan T.L.Collins & I.Telford, X. neoanglicum J.J.Bruhl & I.Telford, X. strictum T.L.Collins, and X. wilsonii T.L.Collins, reinstate Helichrysum banksii A.Cunn. ex DC. (as X. banksii (A.Cunn. ex DC.) T.L.Collins & I.Telford), lectotypify X. banksii and X. papillosum (Labill.) R.J.Bayer, and recircumscribe X. bicolor (Lindl.) R.J.Bayer to include X. halmaturorum Paul G.Wilson and some populations of X. bracteatum sens. lat. from mainland South Australia and Victoria. We also provide revised descriptions of all taxa in the genus, their conservation status, a dichotomous key, tables distinguishing closely related taxa and distribution maps
Quantifying Phytogeographical Regions of Australia Using Geospatial Turnover in Species Composition
The largest digitized dataset of land plant distributions in Australia assembled to date (750,741 georeferenced herbarium records; 6,043 species) was used to partition the Australian continent into phytogeographical regions. We used a set of six widely distributed vascular plant groups and three non-vascular plant groups which together occur in a variety of landscapes/habitats across Australia. Phytogeographical regions were identified using quantitative analyses of species turnover, the rate of change in species composition between sites, calculated as Simpson's beta. We propose six major phytogeographical regions for Australia: Northern, Northern Desert, Eremaean, Eastern Queensland, Euronotian and South-Western. Our new phytogeographical regions show a spatial agreement of 65% with respect to previously defined phytogeographical regions of Australia. We also confirm that these new regions are in general agreement with the biomes of Australia and other contemporary biogeographical classifications. To assess the meaningfulness of the proposed phytogeographical regions, we evaluated how they relate to broad scale environmental gradients. Physiographic factors such as geology do not have a strong correspondence with our proposed regions. Instead, we identified climate as the main environmental driver. The use of an unprecedentedly large dataset of multiple plant groups, coupled with an explicit quantitative analysis, makes this study novel and allows an improved historical bioregionalization scheme for Australian plants. Our analyses show that: (1) there is considerable overlap between our results and older biogeographic classifications; (2) phytogeographical regions based on species turnover can be a powerful tool to further partition the landscape into meaningful units; (3) further studies using phylogenetic turnover metrics are needed to test the taxonomic areas
Using amplified fragment length polymorphism (AFLP) to unravel species relationships and delimitations in Minthostachys (Labiatae)
Minthostachys (Benth.) Spach (Labiatae) is a South American genus of aromatic shrubs frequently collected as a condiment, for the preparation of tea, or for medicinal purposes. Notoriously difficult species delimitation, conflicting taxonomic treatments of the past, and the lack of a revision with modern methods have hampered the understanding of this ecologically and economically interesting group. The amplified fragment length polymorphism (AFLP) study presented in this paper supplements field and morphological studies within the framework of a taxonomic and systematic revision. AFLP is found to be unsuitable for the reconstruction of the phylogeny of Minthostachys. Although, in some cases, morphologically well-defined species are also genetically distinct, extensive gene flow seems to occur between strikingly different species growing in the immediate vicinity and even between Minthostachys and Clinopodium (Xenopoma) vanum. Samples from the most complicated species, M. mollis, are genetically very heterogeneous and mostly fall into two clusters according to their geographical origin, exhibiting a high discrepancy with the pattern of morphological variation. (c) 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153, 9-19
Phylogenetic relationships of the Australasian shrubby everlastings Ozothamnus and Cassinia (Asteraceae: Asteroideae: Gnaphalieae)
The first comprehensive phylogenetic study of the Australasian shrubby everlastings Ozothamnus, Cassinia, and their satellite genera is presented based on the nuclear ribosomal external and internal transcribed spacer and three chloroplast spacer region
SYNOPTKEY: a PHP program for online presentation of synoptic determination keys
SCHMIDT-LEBUHN, A.N. & KESSLER, M. 2007: SYNOPTKEY – ein PHP-Programm für Online-Präsentation synoptischer Bestimmungsschlüssel. Schlechtendalia 16: 101–105.Synoptische Schlüssel haben gegenüber analytischen Schlüsseln einige Vorteile, werden aber seit langer Zeit wegen ihrer schwer handhabbaren Größe kaum genutzt. Mit dem Aufkommen elektronischer Datenspeicherung und von Online-Floren wurde jedoch deren Nutzung immer praktikabler.SYNOPTKEY ist ein kurzes PHP-Programm, welches in Web-Seiten integriert werden kann, um synoptische Online-Bestimmungsschlüssel verfügbar zu machen. Es kann unter folgender Webadresse heruntergeladen werden: http://www.minthostachys.com/files/synoptkey.zip.Datensätze, die für das Programm nutzbar sind, können mit üblicher Tabellenkalkulationssoftware erstellt werden, z.B. MS Excel, StarCalc, etc.SCHMIDT-LEBUHN, A.N. & KESSLER, M. 2007: SYNOPTKEY – a PHP program for online presentation of synoptic determination keys. Schlechtendalia 16: 101–105.Synoptic keys have several advantages over analytic keys, but for a long time were rarely used due to their unwieldy size in print. With the advent of electronic data storage and online floras, their implementation has become more practical. SYNOPTKEY is a short PHP program that can be integratedinto websites to provide online synoptic determination keys. It is available for download under http://www.minthostachys.com/files/synoptkey.zip. Data files to be used by the program can be prepared with standard spreadsheet calculation software, e.g. MS Excel, StarCalc, etc.Die Schlechtendalia publiziert Originalbeiträge mit Schwerpunkt Spezielle Botanik und Biodiversität, Floristik, Mykologie/Lichenologie, Wissenschaftsgeschichte und andere Themen mit Bezug zu Botanischen Gärten und Herbarien