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– Principal coordinate analysis based on 51 morphological characters of 46 field-collected populations from the Cyanus triumfetti group in Central Europe: ª 'C. axillaris', C. strictus ( area close to the type locality of Centaurea stricta).
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Multivariate morphometrics and an assessment of genetic diversity obtained using amplified fragment length polymorphism (AFLP) were used to determine the variability of the polymorphic group Cyanus triumfetti in Central Europe. The ploidy level of the populations studied was also determined; all individuals from the C. triumfetti group were diploid...
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Multivariate morphometrics and an assessment of genetic diversity obtained using amplified fragment length polymorphism (AFLP) were used to determine the variability of the polymorphic group Cyanus triumfetti in Central Europe. The ploidy level of the populations studied was also determined; all individuals from the C. triumfetti group were diploid...
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... Moreover, intermediate morphotypes among some taxa are also reported (cf. Olšavská et al. 2011). The patterns of genetic diversity in the C. triumfetti group obtained by AFLP markers (Olšavská et al. 2011) and nuclear DNA sequences (Löser, unpubl. ...
... Olšavská et al. 2011). The patterns of genetic diversity in the C. triumfetti group obtained by AFLP markers (Olšavská et al. 2011) and nuclear DNA sequences (Löser, unpubl. data) reflect its geographic distribution. ...
... The weak genetic differentiation revealed for morphologically well-separated taxa from Slovakia and Hungary ('C. axillaris' and C. dominii, C. strictus) could indicate a very recent diversification or ongoing gene flow (Olšavská et al. 2011). Plants of the C. triumfetti and C. montanus groups are insect-pollinated, mainly by honeybees, bumblebees, wasps and ants (Hymenoptera). ...
Mode of reproduction and presence of reproductive barriers were studied in two closely related members of the genus Cyanus: the C. triumfetti (diploid 2n = 22) and C. montanus (tetraploid 2n = 44) groups. Based on results from isolation and emasculation experiments, taxa of these groups can be considered allogamous with a low selfing rate (0.07 %–0.21 % of achenes developed after selfing). Taxa of the C. triumfetti group hybridize easily and produce viable progeny. Differences in the percentage of well-developed achenes per capitulum obtained from interspecific crosses between members of the C. triumfetti group suggested different levels of reproductive isolation. The percentage of well-developed achenes of most homoploid crosses was 3.47 %–8.87 %. Higher percentages of well-developed achenes were obtained from crosses between Eastern Carpathian C. pinnatifidus and Alpine C. triumfetti s. str. (18.36 % ; 26.56 %) and between geographically close taxa in Central Europe (C. dominii, C. strictus and ‘intermediate morphotype’; 12.75 % –17.60 %), which indicate their overall close relatedness. Crossing geographically remote C. strictus and C. triumfetti s. str. yielded no or only few (0.99 %) well-developed achenes, indicating an increased degree of incompatibility in allopatry. The success of heteroploid crosses between plants belonging to different groups was reduced (2.96 %) and suggested reproductive incompatibilities between ploidy levels. The progeny of heteroploid crosses comprised 63 % of triploids of presumable hybrid origin on tetraploid as well as diploid maternal plants. Another 15.22 % of progeny had the maternal cytotype, probably resulting from selfing. Low viability of heteroploid hybrids supports the existence of post-zygotic mechanisms.
Tephroseris longifolia agg. is an intricate complex of perennial outcrossing herbaceous plants. Recently, five subspecies with rather separate distributions and different geographic patterns were assigned to the aggregate: T. longifolia subsp. longifolia, subsp. pseudocrispa and subsp. gaudinii predominate in the Eastern Alps; the distribution of subsp. brachychaeta is confined to the northern and central Apennines and subsp. moravica is endemic in the Western Carpathians. Carpathian taxon T. l. subsp. moravica is known only from nine localities in Slovakia and the Czech Republic and is treated as an endangered taxon of European importance (according to Natura 2000 network). As the taxonomy of this aggregate is not comprehensively elaborated the aim of this study was to detect variability within the Tephroseris longifolia agg. using methods of plant systematics (multivariate morphometrics of 525 individuals/33 populations based on 49 characters, DAPI flow cytometry of 98 individuals/33 populations). The relative DNA content at the homoploid level (2n ∼ 6x ∼ 48) varied by 25.8% and significant taxa-specific differences were confirmed among plants of T. l. subsp. pseudocrispa, subsp. gaudinii, subsp. brachychaeta and a group consisting of T. l. subsp. moravica and subsp. longifolia. The morphometric study indicated six morphotypes roughly corresponding to the previously distinguished subspecies. The exceptions were populations traditionally assigned to T. l. subsp. longifolia, for which two distinct morphotypes with different geographic origins were identified: Alpine morphotype and Pannonian morphotype. In general, the differences in DNA content and morphology argue for a classification at the species level for plants of T. l. subsp. brachychaeta, while differences among other morphotypes fit a subspecific level. Surprisingly, Pannonian populations of T. l. subsp. longifolia are morphologically closer to populations of the Western-Carpathian endemic subsp. moravica than to Alpine populations of nominate subspecies. Based on this, the taxonomic position of Pannonian morphotype and subsequently the endemic status of T. l. subsp. moravica require further study. A key for identifying the taxa and morphotypes of Tephroseris longifolia agg. in central Europe is presented.
In this paper, we summarize the results of our long-date research on the genus Centaurea. The first part of the paper deals with the overall classification of the genus, which we propose to divide into three subgenera: subgenus Centaurea, subgenus Cyanus and subgenus Lopholoma. The second part of this publication gives a recopilation of the species of the redefined section Centaurea, a group that includes former sections Acrolophus (sect. Centaurea s. str.), Phalolepis and Willkommia, together with taxonomical, geographical, ecological and karyological considerations. Finally, new descriptions or nomenclatural combinations are proposed to correlate nomenclature to the new classification: a new combination (sect. Acrocentron subsect. Chamaecyanus) is proposed in subgenus Lopholoma; three new sections (sects. Akamantis, Cnicus, and Hyerapolitanae) are described in subgenus Centaurea; two subsections (subsects. Phalolepis and Willkommia) in sect. Centaurea; and three subsections (subsects. Exarata, Jacea, and Subtilis) in sect. Phrygia.
To reveal the general cytogeographical pattern of Cyanus section Protocyanus in Europe, DNA ploidy and/or chromosome numbers were newly examined for 160 populations by flow cytometry (450 plants) and/or chromosome counting (30 plants). Furthermore, previously published karyological data were revised (236 records). Our analyses confirmed chromosome counts of 2n = 22 for all newly investigated samples of the C. triumfetti group (the records for C. semidecurrens and C. ternopoliensis are new), C. diospolitanus and C. achtarovii; 2n = 44 for C. montanus and C. mollis; and 2n = 20 for C. lingulatus, C. napulifer, C. nissanus, C. orbelicus, C. thirkei, C. tuberosus and C. velenovskyi. The chromosome count of 2n = 20 is the first report for C. epirotus. The cytotype 2n = 40 was newly recorded for the Crimean endemic C. fuscomarginatus and Calabrian and Greek populations of C. graminifolius. The cytotypes 2n = 20 and 2n = 40 were confirmed for C. pindicola. For the first time triploidy (2n∼3x∼30) was found in C. nissanus, C. thirkei and in a newly discovered hybrid, C. epirotus × C. graminifolius. Two contrasting ecogeographical patterns emerged: cytotypes derived from the base chromosome number x = 11 (2n = 22, 44) are widespread in northern latitudes and ecologically diverse, whereas cytotypes with x = 10 (2n = 20, 30, 40) are confined to mountains in southern Europe. In general, tetraploids have smaller ranges than diploids. The new combinations Cyanus section Protocyanus (Dobrocz.) Olšavská comb. nov. and Cyanus ternopoliensis (Dobrocz.) Olšavská comb. nov. are provided.
A population of Centaurea weldeniana was discovered recently near Wien (Vienna). The species is reported from Austria for the first time. Determination is confirmed by morphometric analysis of Central European and additional Balkan material of the C. jacea agg. and karyological data. All sampled populations of C. weldeniana are diploid, while only tetraploids have been reported from Central Europe within the C. jacea agg. so far. Detailed morphometric analysis of the newly discovered C. weldeniana population revealed several hybrids with tetraploid C. jacea. The hybrids are tetraploid and originate from unreduced gametes of diploids. No triploids were found. Indeed, the incidence of hybridization is surprisingly low. The population was probably discovered already in 1886 (determined as C. bracteata) and was described as a new species C. argyrolepis in 1901, but these data were lost. However, this isolated diploid population has survived for at least 125 years, which provides a good example of the strength of inter-cytotype reproductive barriers in Centaurea sect. Jacea.
The genome size of 265 plants and the GC content of 126 plants from 63 populations of the Cyanus triumfetti and Cyanus montanus groups, collected across the Carpathians, Pannonia, Bohemian Massif, and Western and Dinaric Alps were determined by PI and DAPI flow cytometry. Variation of the nuclear DNA content among homoploid species, and intraspecific and interpopulation variation were confirmed in simultaneous analyses. The 2C-value at the diploid level (the C. triumfetti group) varied from 2.53 for Cyanus dominii subsp. sokolensis to 3.06 pg for C. triumfetti s.s. (1.21-fold range). At the tetraploid level (the C. montanus group), the 2C-value varied from 5.19 for Cyanus mollis to 5.84 pg for C. montanus (1.13-fold range). High intraspecific and interpopulation variation in the amount of nuclear DNA in the C. triumfetti group correlates with the extensive morphological variation found in this group. Significant between-species differences in genome size indicate that this attribute may be used as a supportive taxonomic marker for both of the groups studied. The GC content varied by 2.93 %, from 39.46 % for “Cyanus axillaris” to 40.61 % for Cyanus adscendens; this character is of no value for taxonomic purposes. Genome size of the studied populations is significantly higher in southern parts of the distribution area and at higher elevations. Plants with smaller genomes tend to occur in dry areas at low altitudes with high diurnal and annual temperature oscillations. The GC content of the populations studied is significantly correlated with longitude, increasing from east to west; and plants with GC-rich genomes are concentrated in the coldest areas with low minimum temperatures.
