Search results for "Disjunct"

Repeat intercontinental dispersal and Pleistocene speciation in disjunct Mediterranean and desert Senecio (Asteraceae).

2003

To explore the biogeographic history of Mediterranean/arid plant disjunctions, Old and New World Senecio sect. Senecio were analyzed phylogenetically using nuclear ribosomal DNA sequences (ITS). A clade corresponding to sect. Senecio was strongly supported. Area optimization indicated this clade to be of southern African origin. The Mediterranean and southern African floras were not distinguishable as sources of the main New World lineage, estimated to have become established during the middle Pliocene. Another previously suspected recent dispersal to the New World from the Mediterranean was confirmed for the recently recognized disjunction in S. mohavensis. The loss of suitable land connec…

A taxonomic revision of the Capparis spinosa group (Capparaceae) from the Mediterranean to Central Asia

2014

A revision of the Capparis spinosa group has been carried out in southern Europe, northern Africa, western and central Asia, in order to provide a uniform taxonomic treatment of its representatives. The xerotropical origin of this group, showing disjunct distribution in several holoarctic and paleotropical regions, is underlined and the different species concepts historically adopted are discussed. In the present treatment a single species is recognized, C. spinosa , represented in the study area by two subspecies. C. spinosa subsp. spinosa shows derived characters, high polymorphism and a wide distribution range from the Mediterranean eastwards to China and Nepal. C. spinosa subsp. rupestr…

Molecular phylogeny of the harvestmen genus Sabacon (Arachnida: Opiliones: Dyspnoi) reveals multiple Eocene–Oligocene intercontinental dispersal even…

2012

Abstract We investigated the phylogeny and biogeographic history of the Holarctic harvestmen genus Sabacon , which shows an intercontinental disjunct distribution and is presumed to be a relatively old taxon. Molecular phylogenetic relationships of Sabacon were estimated using multiple gene regions and Bayesian inference for a comprehensive Sabacon sample. Molecular clock analyses, using relaxed clock models implemented in BEAST, are applied to date divergence events. Biogeographic scenarios utilizing S-DIVA and Lagrange C++ are reconstructed over sets of Bayesian trees, allowing for the incorporation of phylogenetic uncertainty and quantification of alternative reconstructions over time. F…

Unnoticed diversity within the disjunct moss Orthotrichum tenellum s.l. validated by morphological and molecular approaches

2013

So close yet so far: the disjunct global range of Orthotrichum consobrinum (Orthotrichaceae) includes North America

2021

Three intercontinental disjunctions in Papaveraceae subfamily Chelidonioideae: evidence from chloroplast DNA

1995

An RFLP analysis of the chloroplast genome of Papaveraceae subfam. Chelidonioideae resulted in one most parsimonious tree consisting of three monophyletic groups. Each group contains intercontinental disjunct taxa. Whereas Eomecon/Sanguinaria and Stylophorum are examples for the well known E Asian — eastern N American disjunction, the E Asian -C and S American disjunction in Macleaya/Bocconia is rare. The genus Stylophorum in this analysis is paraphyletic. The N American Stylophorum diphyllum is sister group to the Old World members of Stylophorum and Chelidonium. All American representatives of the subfamily possess distinctive morphological features. This might be the result of Tertiary a…

Phylogeny and Biogeography of <I>Epimedium</I>/<I>Vancouveria</I> (Berberidaceae): Western North American - East Asian Disjun…

2007

Using ITS and atpB-rbcL spacer sequences of 38 (of 55) species of the highly disjunct Eurasian/North African Epimedium and all three species of its western North American sister genus Vancouveria, we reconstructed the phylogeny of these two genera and dated major splits with a molecular clock approach. Epimedium was found to be monophyletic with a stem age dated to between 9.7 and 7.4 million years ago (My). Within Epimedium, almost all sections as recognized in the most recent classification of the genus were found to be monophyletic but subg. Epimedium was found to be paraphyletic in relation to subg. Rhizophyllum. Range formation in Eurasia proceeded as follows: in a first step, the west…

Chloroplast DNA evidence for introgression and long distance dispersal in the desert annualSenecio flavus (Asteraceae)

1995

Phylogenetic analysis of chloroplast DNA (cpDNA) restriction site variation supports a close genetic relationship between the Southwest AsianSenecio flavus subsp.breviflorus and the North AmericanS. mohavensis. The intercontinental disjunct distribution of these two desert annuals may have originated via long distance dispersal. The chloroplast genomes of the Southern and North AfricanS. flavus subsp.flavus and subsp.breviflorus differ by at least ten restriction sites, while at most two restriction sites differentiate the cpDNA genomes of subsp.breviflorus and the outgroupS. squalidus. This suggests that the cpDNA genome ofS. flavus subsp.breviflorus may have resulted from introgression an…

Testing the ontogenetic base for the transient model of inflorescence development

2013

† Backgrounds and Aims: Current research in plant science has concentrated on revealing ontogenetic processes of key attributes in plant evolution. One recently discussed model is the ‘transient model’ successful in explaining some types of inflorescence architectures based on two main principles: the decline of the so called ‘vegetativeness’ (veg) factor and the transient nature of apical meristems in developing inflorescences. This study examines whether both principles find a concrete ontogenetic correlate in inflorescence development. † Methods: To test the ontogenetic base of veg decline and the transient character of apical meristems the ontogeny of meristematic size in developing inf…

Algebraic aspects and coherence conditions for conjoined and disjoined conditionals

2019

We deepen the study of conjoined and disjoined conditional events in the setting of coherence. These objects, differently from other approaches, are defined in the framework of conditional random quantities. We show that some well known properties, valid in the case of unconditional events, still hold in our approach to logical operations among conditional events. In particular we prove a decomposition formula and a related additive property. Then, we introduce the set of conditional constituents generated by $n$ conditional events and we show that they satisfy the basic properties valid in the case of unconditional events. We obtain a generalized inclusion-exclusion formula and we prove a …