Jestřábník okoličnatý (Hieracium umbellatum) v České republice
| Title in English | Hieracium umbellatum in the Czech Republic |
|---|---|
| Authors | |
| Year of publication | 2014 |
| Type | Article in Periodical |
| Magazine / Source | Acta rerum naturalium |
| MU Faculty or unit | |
| Citation | |
| Field | Botany |
| Keywords | Asteraceae; Central Europe; chromosome numbers; phytogeography; taxonomy |
| Description | The distribution of Hieracium umbellatum in the Czech Republic was studied based on herbarium specimens stored in 29 public herbaria. This species, classifi ed within H. sect. Hieracioides, is one of 57 native hawkweeds (Hieracium s. str.) of the Czech flora. From H. sabaudum, the most similar species, it may be distinguished mainly by recurved involucral bracts, umbelliform synflorescence (at least in the upper part), revolute leaf margins, usually narrower leaves and yellow styles. Using flow cytometry measurements and chromosome counts, four plants originating from two populations (two plants per population) from the south-eastern part of Czechia were shown to be diploid (2n ~ 2x) and one plant had 2n = 18, respectively. We revised 1,428 herbarium specimens of this species collected in the country, of which 1,116 (i.e. about 78%) were identified correctly (including taxonomic synonyms). However, a further 80 specimens originally identified as H. umbellatum were revised as H. sabaudum. Hieracium umbellatum occurs with different frequencies in most parts of the country; however, it is rare or absent from some parts of western, eastern and south-eastern Bohemia and northern, southwestern and eastern Moravia. In the Czech National Phytosociological Database, its occurrence is documented in a broad scale of different plant communities, most frequently in dry grasslands, wet meadows of the Molinion alliance and thermophilous oak forests. The occurrence of H. vasconicum (syn. H. laurinum), a taxon morphologically intermediate between H. umbellatum and H. sabaudum, in the Czech Republic requires further research. |
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