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Zprávy České botanické společnosti 41/1, 2006


Krahulec F., Duchoslav M. & Bártová V.
Rozšíření druhů rodu česnek (Allium) v České republice. I. Druhy sekcí Reticulato­bulbosa, Butomissa a Anguinum (A. strictum, A. tuberosum, A. victorialis)
Geographical distribution of Allium species in the Czech Republic. I. Species of sect. Reticulato­bulbosa, Butomissa and Anguinum (A. strictum, A. tuberosum, A. victorialis)

The distribution of three species of the genus Allium sect. Reticulato-bulbosa, Butomissa and Anguinum (Allium strictum, A. tuberosum, A. victorialis) was studied on the territory of the Czech Republic. A. strictum is a rare relic species occurring at approximately 30 localities in Central and North Bohemia. The highest number of localities occurs in Prague City and its surroundings. A. strictum occurs in rock-outcrop vegetation of the Alysso-Festucion pallentis alliance and it is found rarely in continental pine forests of the Dicrano-Pinion alliance. A. tuberosum is an allochthonous species of the Czech flora. It was repeatedly collected in the period between 1866 and 1942 on the margin of diabas rock at Velká Chuchle near Prague. At present, it is sometimes cultivated in gardens and rarely escapes. A. victorialis is a rare species that occurs in subalpine tall grasslands and subalpine and montane Nardus-grasslands in the three mountain ranges: Krkonoše Mts, Hrubý Jeseník Mts, and Moravskoslezské Beskydy Mts. During the 20th century, it disappeared from most localities in the Hrubý Jeseník Mts. In addition, two isolated localities occur at lower altitudes near the village of Boršice (White Carpathians Mts) and near the town of Havířov (Ostravská pánev region).

Ducháček M., Hroudová Z. & Marhold K.
Rod Bolboschoenus v květeně České republiky I. Bolboschoenus maritimus s. str., B. planiculmis, B. glaucus
The genus Bolboschoenus in the Czech Republic I. Bolboschoenus maritimus s. str., B. planiculmis, B. glaucus

A survey of taxonomical problems within the genus Bolboschoenus in Europe together with a determination key to Bolboschoenus species growing in the Czech Republic are given. In addition, taxonomy, habitat characteristics and distribution in the Czech Republic of Bolboschoenus maritimus s.str., B. planiculmis and B. glaucus are presented. B. maritimus is a facultative halophyte occurring on fragments of saline wetlands or in secondary habitats on sites of former saline habitats. It is a rare species in the Czech Republic. B. planiculmis inhabits mostly terrestrial habitats temporarily flooded, on mineral-rich grounds. Its distribution overlaps that of B. maritimus, but B. planiculmis was found more frequently. Recently it spreads as a weed in humid crop fields. B. glaucus has been found at one locality in Prague City. Owing to the secondary character of the habitat and isolated position of the locality, B. glaucus is supposed to be introduced.

Chán V., Trávníček B. & Žíla V.
Příspěvek k rozšíření druhů rodu Taraxacum v jižní části Čech. III. (se 6 novými druhy pro květenu České republiky)
Contribution to the knowledge of Taraxacum species distribution in South Bohemia III (with six new species for the Czech flora)

Results of taraxacological investigations in South Bohemia performed in the years (1995–)1999–2004 are presented. 70 species of the genus Taraxacum were found. The following six species are new to the Czech Republic: T. reichlingii van Soest of sect. Celtica A. J. Richards and T. aberrans Hagendijk, van Soest & Zevenbergen, T. flavostylum Bäck, T. gesticulans H. Ollgaard, T. gibberum Markl. and T. pulverulentum H. Ollgaard of sect. Ruderalia Kirschner, H. Ollgaard & Štěpánek. Illustrations of the new Czech Taraxacum species and T. violaceinervosum Railons. are provided.

Sutorý K.
Opletník sličný (Calystegia pulchra) – doplňky k rozšíření v České republice
Calystegia pulchra – additions to the distribution in the Czech Republic

New and omitted data of the distribution of Calystegia pulchra on the territory of the Czech Republic are given.

Blažková D.
Co popisuje fytocenologie – odpověď
What is described by phytosociology? A reply

A hierarchical phytosociological system is NOT the main purpose of phytosociology. It is only a means to process the information in such a way that the general attributes, common to the phytosociological units, can be implied based on the assignment of a stand to a particular phytosociological unit. With a good phytocoenological system, this assignment can be carried out by using a few of the most obvious floristic characters, both qualitative and quantitative. The plant species that build the community can serve as indicators of abstract classification units. For the purpose of classification and definition of phytosociological units, the species that occur in relevés do not need to have the same amount of information about that particular unit. The ordinary, subjectively selected relevés should be augmented with notes that would contain additional species combinations overed in the sampled relevés. The phytosociological classification of successional stages poses a special problem, both in the study of plant communities and the application of the phytosociological system. The utmost attention should be paid to the study of newly formed plant communities that originate from the succession of agrocoenoses.

Češka A.
Bias – předpojatost

On two historical examples, the author tries to show that, under certain conditions, both the investigators’ bias and their ignorance had their place in serious scientific investigations. A simple test at the end of this article not only gives the opportunity to the potential readers to test their bias or ignorance, but it also underscores the absurdity of this question.

Černý T.
Hédl R. (2005): Co popisuje fytocenologie – odpověď
Hédl R. (2005): What is described by phytosociology? A reply

In a critique of Central European phytosociology by R. Hédl the terms ”author bias” and ”methodology bias” have been erroneously used and mutually confused. The first one – bias caused by an enormous number of authors collecting and synthesizing phytosociological data – is worth discussing and analysing, but it is really difficult to assess the objective relation between the status of studied ecosystems (plant assemblages) and types of collected data. The author criticises wrong methodical premises of the discipline and a distortion of hypotheses in the beginning of the development of the discipline, but such arguments are misleading and fallacious, as is explained among others by citations from an early phytosociological textbook. The main problem of disproportion between traditionally described vegetation units and the actual status of vegetation cover does not stems from a wrong methodology, but from requirements of two different approaches – phytosociology and mapping of earth surface. Also, there is a strong ”scale bias”, i.e. the scale of phytosociological relevés and the landscape scale. Both scales are very hardly parallelised and we cannot avoid a bias when interpreting gross-scaled phenomena by studying fine-scaled ones. Research solving such problems of scaling is not included in well-established and long-practised phytosociological sampling of vegetation. Currently, the established phytosociological system does not treat systematically the whole vegetation cover. This situation is not caused by a gap or inconsistency in methodology, but by phytosociologists focusing on sampling data in well-developed landscape regions, such as protected areas and nature reserves. We should concentrate now on completing our knowledge and data in terms of composition and structure of vegetation covering a common and anthropogenically impoverished landscape.