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Abstrakty/Abstracts

Zprávy České botanické společnosti 48/2, 2013


Abstrakty/Abstracts

Prančl J.
Rod Callitriche (hvězdoš) v České republice. II. C. cophocarpa, C. stagnalis, C. platycarpa, C. xvigens
The genus Callitriche (water-starwort) in the Czech Republic. II. C. cophocarpa, C. stagnalis, C. platycarpa, C. xvigens

Abstract
The second part of a complete revision of the genus Callitriche in the Czech Republic is presented. Four taxa are described in detail, and their ecological demands and distribution are discussed. Callitriche cophocarpa, probably the most abundant species of the genus, occurs in various types of standing and running waters from lowlands to mountains, except the extreme north of Bohemia, where it is possibly absent. Callitriche stagnalis most often grows in puddles on forest paths. It occurs nearly throughout the territory, but is surprisingly absent from South Moravia. Callitriche platycarpa has a markedly Subatlantic distribution. It is known from northern, northwestern and western Bohemia, forming the eastern border of its distribution. It inhabits a wide range of habitats, but the ecological optimum of this species is in streams with a muddy bottom. C. platycarpa is partially vicariant with C. cophocarpa, which has a rather Continental distribution. The hybrid C. ×vigens (C. cophocarpa × C. platycarpa) has been found in the Czech Republic for the first time. It can be found in areas where both parental species occur, and might be not so rare. However, it was also found in the Otava river, where C. platycarpa is not known to occur. Callitriche obtusangula, a species whose presence in the Czech Republic was reported to be probable according to some sources, has actually never been found in this country.

Ekrt L., Linhartová R. & Štech M.
Rozlišování a revize rozšíření kapradě podobné (Dryopteris expansa) a jejího křížence D. xambroseae v České republice
Differentiation of Dryopteris expansa and its hybrid D. xambroseae and revision of their distribution in the Czech Republic

Abstract
The distribution of Dryopteris expansa and D. ×ambroseae (D. dilatata × D. expansa) was studied in the Czech Republic. Collections from 22 Czech public herbaria were revised and a total of 479 specimens were examined. The hybrid D. ×ambroseae often occurs together with D. expansa. In the Czech Republic, the greatest frequency of D. expansa was recorded at locations with a high air moisture (e.g. mountain areas and foothills with beech and spruce forests). At lower altitudes, the species occurs in deep valleys with alder forests along streams and rivers or around springs. Dryopteris expansa is very common in gorges and canyons in sandstone areas in the Czech Cretaceous Basin (Česká křídová pánev) and scattered on cold screes of the hills of České středohoří Mts. Lowland occurrences were rarely detected in alluvial forests. Dryopteris expansa occurs at altitudes from 200 to 1420 m and most frequently at altitudes from 500 to 700 m. A short summary of the taxonomy and hybridisation in the D. carthusiana group is given. An identification key, distribution maps and notes to the differentiation, hybridisation and habitat preferences are presented as well.

Ekrtová E.
Co se můžeme dozvědět o historii výskytu hořce panonského (Gentiana pannonica) v centrální oblasti Šumavy z jeho současného rozšíření, stanovištních vazeb a historického využívání krajiny
What we can learn about the history of Gentiana pannonica in the central area of the Bohemian forest from its current distribution, habitat demands and historical land use

Abstract
The distribution and habitats of the rare species Gentiana pannonica were studied in the central part of the Bohemian Forest. The study area represents the centre of the current distribution of Gpannonica in the Czech Republic. In the Bohemian Forest, Gpannonica is a typical glacial relict bound to non-forest habitats (cirques of glacial lakes, banks of streams, secondary montane meadows). The most frequent habitats of the species are short-grasslands and heaths in secondary, forest-free areas or early successional stands with woody species. Occurrence at small open sites along banks of forest streams is typical as well. At localities with presence of G. pannonica, historical maps were used to determine the habitat types approximately 160 years ago. Pastures, dry meadows, and forests represent the most common “historical” type of habitat at localities with the gentians. Based on these results, it is assumed that open sites along streams represent the most important type of primary habitat in the central part of the Bohemian Forest. It seems that specific human activities (e.g. cultivation in gardens and fields) have affected the general distribution of the species in the study area only marginally. Currently, G. pannonica occurs in numerous populations in the centre of the Bohemian Forest, especially in secondary forest-free enclaves. However, successional processes negatively affect population size, flowering, and habitat quality.