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Number of results: 8
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Abstract

Abstract Chromosome numbers for 16 Hieracium s.str. species from Bosnia and Herzegovina, Bulgaria, Macedonia, Montenegro, Poland, Romania and Serbia are given and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. filarszkyi Jáv. & Zahn 2n = 3x = 27, H. fritschianum Hayek & Zahn 2n = 3x = 27, H. fritzeiforme Zahn 2n = 3x = 27, H. hercegovinicum (Freyn & Vandas) Szeląg 2n=3x=27, H. nivimontis (Oborny & Zahn) Chrtek fil. 2n = 4x = 36, H. vagneri Pax 2n = 4x = 36, as well as three undescribed species of hybrid origin between H. olympicum Boiss. and H. sparsum Friv. 2n = 4x = 36, H. naegelianum Panc. and H. scardicum Bornm. & Zahn 2n = 3x = 27, and H. transylvanicum Heuff. and H. umbellatum L. 2n = 4x = 36.
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Abstract

Abstract Karyology of eleven species of Taraxacum sect. Erythrosperma from Poland has been studied. Somatic chromosome numbers are given for the following species: T. bellicum, T. brachyglossum, T. cristatum, T. disseminatum, T. dissimile, T. lacistophyllum, T. parnassicum, T. plumbeum, T. proximum, T. scanicum, and T. tenuilobum. Although the hypertriploid chromosome number was previously reported in Poland for T. lacistophyllum, T. parnassicum, T. scanicum, and T. tenuilobum, we proved the triploid chromosome number 2n = 24 in all the species investigated, which is consistent with the data reported from other regions of Europe. The chromosome numbers of T. bellicum, T. cristatum, T. disseminatum, T. dissimile, T. plumbeum, and T. proximum growing in Poland are published for the first time.
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Abstract

The paper reports a comparative study of the female gametophyte and especially synergid structure in sexual and apomictic dandelions. We analyzed diploid sexually reproducing Taraxacum linearisquameum (2n = 2x = 16) and two triploids, T. alatum and T. udum (2n = 3x =24), with autonomous embryo and endosperm development. There were no observed differences in the organization of the mature megagametophyte between the examined species. Both meiotically reduced and diplosporous embryo sacs showed typical polarity of the egg apparatus cells, together with development of a filiform apparatus in the synergids, but immunocytochemical analyses indicated that microtubules form longitudinal brush-like bundles adjacent to the filiform apparatus in the synergids of the sexual T. linearisquameum. This arrangement of cytoskeletal elements is similar to the configuration described in other amphimictic plants. The synergids of the apomictic T. alatum and T. udum show a uncharacteristic and relatively weak cytoskeleton with no brush-like bundles. We discuss the role of synergids in autonomous apomicts.
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Abstract

Abstract Chromosome numbers for 13 species of Hieracium L. s.str. from Bulgaria, Macedonia, Poland and Romania are given and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. djimilense s.lat. 2n=3x=27, H. fiekii R. Uechtr. 2n=3x=27, H. glabrescens (F. W. Schultz) Murr 2n=3x=27, H. juranomorphum Zahn 2n=3x=27, H. sparsiflorum subsp. sparsiceps Zahn 2n=3x=27 and H. sparsum subsp. naegelianiforme Behr & Zahn 2n=3x=27.
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Abstract

Chromosome numbers for 15 taxa of Hieracium L. s.str. from Bulgaria, Greece, Macedonia, Poland, Romania and Slovakia are given and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. vagneri Pax s.str. (2n = 4x = 36), H. wiesbaurianum subsp. herculanum Zahn (2n = 4x = 36), H. wiesbaurianum subsp. kelainephes Nyár. & Zahn (2n = 3x = 27), as well as for two undescribed species of hybrid origin between H. umbellatum L. and H. wiesbaurianum s.lat. (2n = 3x = 27), and between H. sparsum Friv. and H. schmidtii s.lat. (2n = 3x = 27), and for three undescribed species of the H. djimilense agg. (2n = 3x = 27), H. heldreichii agg. (2n = 3x = 27), and H. sparsum agg. (2n = 3x = 27). Furthermore, the chromosome numbers of two undescribed species of hybrid origin between H. umbellatum L. and H. wiesbaurianum s.lat. (2n = 3x = 27), and between H. sparsum Friv. and H. schmidtii s.lat. (2n = 3x = 27) are given. A new, tetraploid chromosome number is given for H. barbatum Tausch from the northernmost locality of the species in Europe.
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Abstract

Abstract Chromosome numbers for 12 Hieracium s.str. species from Bulgaria, Macedonia, Montenegro, Poland, Romania and Serbia are given and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. albinum Fries 2n=4x=36, H. bukovicae Rohlena & Zahn; 2n=3x=27, H. retyezatense subsp. subatratiforme Neičeff & Zahn 2n=4x=36, H. velenovskyi Freyn 2n=3x=27, as well as two undescribed species belonging to the H. bohatschianum agg. 2n=4x=36 and H. nigrescens agg. 2n=4x=36 and a hybrid between H. naegelianum Pančić and H. bifidum s.lat. 2n=4x=36.
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Abstract

Somatic chromosome numbers are given for the following Taraxacum species: T. pieninicum, 2n=16; T. dentatum, 2n=24; T. fascinans, 2n=24; T. mendax, 2n=40; T. subalpinum, 2n=24; T. telmatophilum, 2n=24; T. cyanolepis, 2n=24; T. fulgidum, 2n=24; T. gentile, 2n=24; and T. undulatum, 2n=24. Chromosome numbers from Poland are published for the first time for T. dentatum, T. fascinans, T. mendax, T. subalpinum, T. telmatophilum, T. cyanolepis, T. fulgidum, T. gentile and T. undulatum.
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