Search results for "Endemism"
showing 10 items of 206 documents
Who threatens who? Natural hybridization between Lotus dorycnium and the island endemic Lotus fulgurans (Fabaceae)
2010
In contrast to its creative role in plant evolution, hybridization may be a cause for concern in efforts to preserve rare and endangered species. Threats can be more acute when population sizes are unequal and when barriers to introgression are weak. Lotus fulgurans is an endangered Balearic Islands endemic shrub related to the widespread Mediterranean species Lotus dorycnium. Both species are morphologically distinct when they grow together. However, morphologically intermediate individuals have been observed on the island of Minorca, in a single, narrowly localized, and apparently stable hybrid zone. Morphological and molecular markers suggest that gene flow between these two Lotus specie…
Population genetic study in the Balearic endemic plant speciesDigitalis minor(Scrophulariaceae) using RAPD markers
2001
Digitalis minor (Scrophulariaceae) is a cardenolide-producing plant endemic to the eastern Balearic Islands (Mallorca, Menorca, and Cabrera) that occurs in two morphologically distinct varieties: D. minor var. minor (pubescent) and D. minor var. palaui (glabrous). Levels and patterns of genetic diversity in 162 individuals from 17 D. minor populations across the entire geographic range were assessed using random amplified polymorphic DNA (RAPD) markers. Comigrating RAPD fragments tested were found to be homologous by Southern hybridization in both var. minor and var. palaui. To avoid bias in parameter estimation, analyses of population genetic structure were restricted to those RAPD bands t…
Distribution, ecology and conservation status of Dionysia involucrata Zaprjag., an endangered endemic of Hissar Mts (Tajikistan, Middle Asia)
2014
<em>Dionysia involucrata</em> Zaprjag. (Primulaceae) is known as critically endangered endemic species of Hissar Mountains in Tajikistan. It is reported from few localities mainly in Varzob River valley and its tributaries. The species inhabits steep or overhanging faces of granite rocks in narrow river gorges. During the research all known populations of <em>D. involucrata</em> were examined in respect of the habitat conditions and species composition of vegetation plots. We analyzed the population extent of the species in its range in Tajikistan and the main threats in order to assess its conservation status. The detrended correspondence analysis was performed on a…
Speciation of sponges in Baikal-Tuva region: an outline
2006
Lake Baikal is known for its high percentage of endemic fauna and flora. The most abundant sessile animal taxa in the littoral zone of Baikal are the photosymbiotic sponges. These endemic sponges are grouped to the family Lubomirskiidae and are separated, based on molecular data, from the cosmopolitan family Spongillidae Gray 1867. In the present review, recent data on the potential driving forces of the rapid speciation in Lake Baikal have been unified. Current data suggest that the genetic repertoire of the sponges was sufficiently large to cope with the major cold events, occurring 2.8–2.5 and 1.8–1.5 Ma. It is proposed that during those periods of climatic incisions founder populations …
Leaf shape variation and taxonomic boundaries in two sympatric rupicolous species of Helichrysum (Asteraceae: Gnaphalieae), assessed by linear measur…
2012
Quantifying and understanding the causes of population differentiation in plants are critical for assessing the taxonomic structure of species, as the level of differentiation among populations may correspond to incipient speciation. Using linear and geometric morphometric approaches, phenotypic variation and associations between leaf traits and geographic and environmental characteristics were investigated in Helichrysum crassifolium and the widespread and sympatric Helichrysum pendulum: two species exhibiting conspicuous leaf variation in size and shape. The morphometric results show that both species have distinct patterns of leaf shape variation. However, overlapping values link the ran…
Hieracium hypochoeroides subsp. peracutisquamum (Asteraceae), a new taxon from Basilicata, (southern Italy)
2015
Hieracium hypochoeroides subsp. peracutisquamum, a new taxon endemic to Basilicata (southern Italy), is described and illustrated. It is confined to the carbonate rocks of Monte della Madonna di Viggiano (Lucanian Apennine, SW Basilicata). Information on its ecology and taxonomic relationships is provided.
A Nomenclatural and Taxonomic Revision of the Senecio squalidus Group (Asteraceae)
2022
Senecio squalidus (Asteraceae) currently includes nine subspecies distributed in North and Central Europe and in the Mediterranean basin. Within this taxonomic aggregate, many species have been described, but research on their nomenclatural types is incomplete. A complete nomenclatural survey of 19 names belonging to this taxonomically critical group was carried out. Fourteen lectotypes are here designated. The nomenclatural analysis, complemented by field investigations in the type localities of the taxa described in the Central Mediterranean, allowed us to accept 10 species. Accordingly, we proposed here a new name and a new missing combination at a specific level: S. aknoulensis and S. c…
A taxonomic reassessment of the Centaurea busambarensis complex (Compositae, Cardueae), with description of a new species from the Egadi Islands (W S…
2017
The results of a statistical biometric study of the Centaurea busambarensis complex, which represents the C. cineraria aggregate in Sicily and its offshore islets, are presented. Seventeen populations, representing all seven previously recognized taxa (four species and three additional subspecies) plus a presumed undescribed one were studied. The statistical analysis (PCA and DA) of 26 morphological characters confirmed these eight taxa as distinct, geographically or ecologically vicarious units of equal weight, not supporting their treatment at different ranks. Consequently, they are recognized here as species, resulting in the description (with illustration) of one of them as new (C. aegu…
Integrative Taxonomy of Armeria arenaria (Plumbaginaceae), with a Special Focus on the Putative Subspecies Endemic to the Apennines
2022
Three subspecies of Armeria arenaria are reported from Italy, two of which are considered endemic to the Apennines. The taxonomic value of these two taxa (A. arenaria subsp. marginata and A. arenaria subsp. apennina) is unclear. Moreover, the relationships between A. arenaria subsp. praecox and Northern Italian populations—currently ascribed to A. arenaria subsp. arenaria—have never been addressed. Accordingly, we used an integrated taxonomic approach, including morphometry, seed morpho–colorimetry, karyology, molecular systematics (psbA–trnH, trnQ–rps16, trnF–trnL, trnL–rpl32, and ITS region), and comparative niche analysis. According to our result…