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Krahulec F., Krahulcová A., Fehrer J., Bräutigam S. & Schuhwerk F. (2008): The structure of the agamic complex of Hieracium subgen. Pilosella in the Šumava Mts and its comparison with other regions in Central Europe. – Preslia 80: 1–26.
We studied the agamic complex of Hieracium subgen. Pilosella in the Šumava/Böhmerwald, the borderland between the Czech Republic and Germany. Their DNA ploidy levels/chromosome numbers, breeding systems, chloroplast haplotypes as well as the clonal structure of apomicts were determined. The complex consists of the following basic and intermediate species and recent hybrids. Basic species: H. aurantiacum L. (tetraploid and pentaploid, both apomictic), H. caespitosum Dumort. (tetraploid, apomictic), H. lactucella Wallr. (diploid, sexual), H. pilosella L. (tetraploid, sexual); intermediate species: H. floribundum Wimm. et Grab. (tetraploid, apomictic), H. glomeratum Froel. (tetraploid and pentaploid, both apomictic), H. scandinavicum Dahlst. (tetraploid, apomictic); recent hybrids: H. floribundum × H. pilosella (partly corresponding to H. piloselliflorum – tetraploid and hexaploid; tetraploid sexual or apomictic), H. glomeratum × H.pilosella (aneuploid, 2n = 38), H. aurantiacum × H. floribundum (tetraploid, almost sterile or apomictic), H. lactucella × H. pilosella (H. schultesii, triploid sterile, tetraploid sexual), H. aurantiacum × H. pilosella (H. stoloniflorum, tetraploid, sexual), H. aurantiacum > H. pilosella (H. rubrum, hexaploid). The hexaploid hybrids between H. pilosella and H. floribundum or H. aurantiacum produced mainly polyhaploid progeny. Two trihaploid plants were found growing in the neighbourhood of their putative hexaploid maternal parent H. rubrum, which is the first record of polyhaploids of this subgenus in the field. Comparison with other mountain ranges (especially the Krušné hory/Erzgebirge, and Krkonoše) with an almost identical composition of basic species, revealed that the structure of the agamic complexes differ.

Trávníček B., Kirschner J. & Štěpánek J. (2008): Five new species of Taraxacum sect. Ruderalia from Central Europe and Denmark. – Preslia 80: 27–59.
A detailed study of Taraxacum sect. Ruderalia for the 8th volume of the Flora of the Czech Republic revealed five new agamospermous species, viz. T. atroviride Štěpánek et Trávníček, T. clarum Kirschner, Štěpánek et Trávníček, T. moldavicum Chán, H. Ollgaard, Štěpánek, Trávníček et Žíla, T. urbicola Kirschner, Štěpánek et Trávníček and T. violaceifrons Trávníček. These species are formally described, thoroughly characterized morphologically and compared with similar taxa. They are known from numerous localities in Central Europe; T. moldavicum, in addition to the Central European distribution, is known to occur in two regions in Denmark. All these species are also documented by photographs of their general habit and important features.

Ricotta C. & Burrascano S. (2008): Beta diversity for functional ecology. – Preslia 80: 61–71.
The utility of biodiversity measures that incorporate pairwise species functional differences is becoming increasingly recognized. Functional diversity is regarded as the key for linking community composition to ecosystem processes like productivity, nutrient cycling, carbon sequestration, or stability when subject to perturbations. Therefore, several indices have been proposed to measure the functional diversity of a given species assemblage. The principle behind these measures is that a species assemblage with high functional overlap among species has a lower functional diversity than an assemblage with low functional overlap. On the other hand, the variability in the species functional characters among different species assemblages (i.e., functional beta diversity) has received much less attention. The aim of this paper is thus to discuss a general framework for calculating functional beta diversity from plot-to-plot functional dissimilarity matrices. To illustrate our proposal we use data from two beech forest stands with different management histories in central Italy. The results of our analysis show that, though the two stands are significantly different from one another in terms of their species functional traits, the difference in their functional beta diversity values is only marginally significant. These results are related to the characteristic scale at which ecological variations occur in the two stands.

Török P., Matus G., Papp M. & Tóthmérész B. (2008): Secondary succession in overgrazed Pannonian sandy grasslands. – Preslia 80: 73–85.
We assessed vegetation changes on acidic sandy soils in permanent plots to follow secondary succession after cessation of intensive goose breeding in E Hungary. We also aimed to estimate the time required for vegetation regeneration and indicate differences in secondary succession patterns at different altitudes in sand dunes. Two sites in the low and two in the high parts of the dunes were chosen and sampled for twelve years. The initial stages are characterized by ruderal communities dominated by nitrophilous annual weeds. Ruderal vegetation was soon replaced by nutrient-poor communities dominated by short-lived pioneer dicotyledonous plants and grasses. In the last few years of the study, coinciding with a rainy period, the low sites were dominated by the perennial grasses, Poa angustifolia , P. pratensis and Cynodon dactylon. In contrast, in the high sites a less dense cover of perennials developed. The influence of initial composition on vegetation development decreased with time and the influence of altitude increased during succession. The altitude of the site had a significant effect on regeneration. Species richness and Shannon diversity of the high sites increased during vegetation development and that of the lowsites decreased. Most annuals persisted in the high sites but became extinct in the low sites. The mean species turnover rate, irrespective of altitude, decreased during the study.

Poulíčková A. (2008): Morphology, cytology and sexual reproduction in the aerophytic cave diatom Luticola dismutica (Bacillariophyceae). – Preslia 80: 87–99.
Monoclonal cultures of the aerophytic cave diatom Luticola dismutica were studied and its frustule morphology, cytology and reproduction recorded. Luticola dismutica is a laterally asymmetrical, monoplastidic pennate diatom with imposed chloroplast division and nuclear behaviour of type 1.A sensu Mann & Stickle. Clones of L. dismutica decreased in cell size in culture until they have reached the sexual size range. Homothallic sexual reproduction and auxosporulation (type IB1a auxosporulation sensu Geitler) were induced in four sexualized clones. Gametangia paired via the girdle, two isogametes were formed per gametangium and hence two zygotes were produced per pair of gametangia. No surviving superfluous nuclei were observed in the gamete and zygote stages and no unfused haploid nuclei were seen in the auxospore stage; zygotes and expanded auxospores had only one nucleus. Auxospores expanded perpendicular to the apical axis of gametangia. Expanded auxospores and initial cells had a swollen central part, the linear-lanceolate outline shape of the vegetative valves was restored during the first divisions of the post-initial cells. Initial cells left the perizonium by a route unique to pennate diatoms, through a transverse rupture of the perizonium. The key cytological and reproductive characteristics reviewed in this paper indicate, that Luticola is more closely related to Placoneis and Dickieia, than to Navicula sensu stricto.

Lambdon P. W., Pyšek P., Basnou C., Hejda M., Arianoutsou M., Essl F., Jarošík V., Pergl J., Winter M., Anastasiu P., Andriopoulos P., Bazos I., Brundu G., Celesti-Grapow L., Chassot P., Delipetrou P., Josefsson M., Kark S., Klotz S., Kokkoris Y., Kühn I., Marchante H., Perglová I., Pino J., Vila M., Zikos A., Roy D. & Hulme P. E. (2008): Alien flora of Europe: species diversity, temporal trends, geographical patterns and research needs. – Preslia 80: 101–149.
The paper provides the first estimate of the composition and structure of alien plants occurring in the wild in the European continent, based on the results of the DAISIE project (2004–2008), funded by the 6th Framework Programme of the European Union and aimed at “creating an inventory of invasive species that threaten European terrestrial, freshwater and marine environments”. The plant section of the DAISIE database is based on national checklists from 48 European countries/regions and Israel; for many of them the data were compiled during the project and for some countries DAISIE collected the first comprehensive checklists of alien species, based on primary data (e.g., Cyprus, Greece, F. Y. R. O. Macedonia, Slovenia, Ukraine). In total, the database contains records of 5789 alien plant species in Europe (including those native to a part of Europe but alien to another part), of which 2843 are alien to Europe (of extra-European origin). The research focus was on naturalized species; there are in total 3749 naturalized aliens in Europe, of which 1780 are alien to Europe. This represents a marked increase compared to 1568 alien species reported by a previous analysis of data in Flora Europaea (1964–1980). Casual aliens were marginally considered and are represented by 1507 species with European origins and 872 species whose native range falls outside Europe. The highest diversity of alien species is concentrated in industrialized countries with a tradition of good botanical recording or intensive recent research. The highest number of all alien species, regardless of status, is reported from Belgium (1969), the United Kingdom (1779) and Czech Republic (1378). The United Kingdom (857), Germany (450), Belgium (447) and Italy (440) are countries with the most naturalized neophytes. The number of naturalized neophytes in European countries is determined mainly by the interaction of temperature and precipitation; it increases with increasing precipitation but only in climatically warm and moderately warm regions. Of the nowadays naturalized neophytes alien to Europe, 50% arrived after 1899, 25% after 1962 and 10% after 1989. At present, approximately 6.2 new species, that are capable of naturalization, are arriving each year. Most alien species have relatively restricted European distributions; half of all naturalized species occur in four or fewer countries/regions, whereas 70% of non-naturalized species occur in only one region. Alien species are drawn from 213 families, dominated by large global plant families which have a weedy tendency and have undergone major radiations in temperate regions (Asteraceae, Poaceae, Rosaceae, Fabaceae, Brassicaceae). There are 1567 genera, which have alien members in European countries, the commonest being globally-diverse genera comprising mainly urban and agricultural weeds (e.g., Amaranthus, Chenopodium and Solanum) or cultivated for ornamental purposes (Cotoneaster, the genus richest in alien species). Only a few large genera which have successfully invaded (e.g., Oenothera, Oxalis, Panicum, Helianthus) are predominantly of non-European origin. Conyza canadensis, Helianthus tuberosus and Robinia pseudoacacia are most widely distributed alien species. Of all naturalized aliens present in Europe, 64.1% occur in industrial habitats and 58.5% on arable land and in parks and gardens. Grasslands and woodlands are also highly invaded, with 37.4 and 31.5%, respectively, of all naturalized aliens in Europe present in these habitats. Mires, bogs and fens are least invaded; only approximately 10% of aliens in Europe occur there. Intentional introductions to Europe (62.8% of the total number of naturalized aliens) prevail over unintentional (37.2%). Ornamental and horticultural introductions escaped from cultivation account for the highest number of species, 52.2% of the total. Among unintentional introductions, contaminants of seed, mineral materials and other commodities are responsible for 1091 alien species introductions to Europe (76.6% of all species introduced unintentionally) and 363 species are assumed to have arrived as stowaways (directly associated with human transport but arriving independently of commodity). Most aliens in Europe have a native range in the same continent (28.6% of all donor region records are from another part of Europe where the plant is native); in terms of species numbers the contribution of Europe as a region of origin is 53.2%. Considering aliens to Europe separately, 45.8% of species have their native distribution in North and South America, 45.9% in Asia, 20.7% in Africa and 5.3% in Australasia. Based on species composition, European alien flora can be classified into five major groups: (1) north-western, comprising Scandinavia and the UK; (2) west-central, extending from Belgium and the Netherlands to Germany and Switzerland; (3) Baltic, including only the former Soviet Baltic states; (4) east-central, comprizing the remainder of central and eastern Europe; (5) southern, covering the entire Mediterranean region. The clustering patterns cut across some European bioclimatic zones; cultural factors such as regional trade links and traditional local preferences for crop, forestry and ornamental species are also important by influencing the introduced species pool. Finally, the paper evaluates a state of the art in the field of plant invasions in Europe, points to research gaps and outlines avenues of further research towards documenting alien plant invasions in Europe. The data are of varying quality and need to be further assessed with respect to the invasion status and residence time of the species included. This concerns especially the naturalized/casual status; so far, this information is available comprehensively for only 19 countries/regions of the 49 considered. Collating an integrated database on the alien flora of Europe can form a principal contribution to developing a European-wide management strategy of alien species.

Liška J., Palice Z. & Slavíková Š. (2008): Checklist and Red List of lichens of the Czech Republic. – Preslia 80: 151–182.
This first version of the Red List of lichens of the Czech Republic uses IUCN criteria version 3.1 for evaluating the species (no infraspecific taxa are included). The Red List is at the same time a new version of the checklist of lichens of the Czech Republic. Differences from the previous checklist published in the Catalogue of lichens of the Czech Republic in 1999 are: 98 species are excluded (non-lichenized fungi, species not documented in the Czech Republic, misidentifications, doubtful/dubious records and other errors) and nomenclatural changes are listed in the chapter on synonyms. In total, 1497 species of lichenized fungi (without lichenicolous and lichen-allied fungi) are included. Of these, 120 (8%) suspicious records and taxonomically problematic or not well explored taxa were not evaluated against the IUCN criteria (NE category). In total, 560 species (37.4%) are threatened: 130 (8.7%) are critically endangered (CR), 184 (12.3%) are endangered (EN) and 246 (16.4%) are vulnerable (VU). In addition, 140 species (9.4%) are extinct in the Czech Republic (RE category), 174 species (11.6%) are listed in the category near threatened (NT) and 190 (12.7%) in least concern (LC). In total, 313 species (20.9%) are listed as data deficient (DD) because insufficient data are available for a categorization.

Chýlová T. & Münzbergová Z. (2008): Past land use co-determines the present distribution of dry grassland plant species. – Preslia 80: 183–198.
Landscapes are constantly changing and, for plant species, this means that some suitable patches disappear while others emerge. Distribution of species in the landscape depends, therefore, not only on actual distribution of suitable habitat patches but also on a species’ ability to persist in habitats that are already unsuitable and disperse to habitats that have become suitable. Distribution of species in such landscapes thus strongly depends on the spatio-temporal structure of the landscape and species traits. The present study aims to determine to what degree past land use affects the present distribution of dry grassland plant species at a regional scale. We studied the distribution of 52 dry grassland species in 215 grassland patches. Data on bedrock, slope, potential irradiation, area and past land use for two periods (1950s and 1980s) were collected from maps. Multivariate analysis was performed to assess the relative contribution of environmental and historical factors on present species distribution. In addition, analyses were carried out to reveal the relationship between past land use and occurrence of single species. This study shows that dry grasslands are habitats with rapid land-use changes. Distribution of species in these habitats is largely determined by environmental conditions, but past land-use also has a significant effect. In many species, the effect of past land use is even more important than the effect of environmental conditions. For the species investigated, those restricted both to former pastures and fields could be identified. Only a minority of species are restricted to continuous grasslands. This indicates that many species colonized places cultivated in 1950 within 50 years, suggesting that the dynamics of these species is relatively fast. The results suggest that many dry grassland communities in the region are of recent origin and the distribution of species in these habitats is partly determined by past land use. In addition to information on environmental conditions, detailed knowledge of land use history, landscape structure and species attributes is needed in order to understand the distribution of species in dry grassland communities.

Douda J. (2008): Formalized classification of the vegetation of alder carr and floodplain forests in the Czech Republic. – Preslia 80: 199–224.
A formalized and supervised phytosociological classification of Alnion glutinosae and Alnion incanae in the Czech Republic is presented. Three associations of Alnion glutinosae (Thelypterido palustris-Alnetum glutinosae, Carici elongatae-Alnetum glutinosae and Carici acutiformis-Alnetum glutinosae) and seven of Alnion incanae (Alnetum incanae, Stellario nemorum-Alnetum glutinosae, Pruno-Fraxinetum, Carici remotae-Fraxinetum, Piceo-Alnetum, Ficario-Ulmetum campestris and Fraxino pannonicae-Ulmetum) were distinguished by the Cocktail method using sociological species groups. Information about their syntaxonomy, species composition, ecology and distribution is presented. Ellenberg’s indicator values were used to show the main ecological gradients responsible for the variation in the vegetation of these communities. The most important factors affecting this variation were temperature (for Alnion incanae) and soil reaction, nutrient availability and moisture (for Alnion glutinosae).

Bureš P. & Danihelka J. (2008): Eleocharis palustris subsp. waltersii, a new name for E. palustris subsp. vulgaris. – Preslia 80: 225–228.
The frequently used subspecific name Eleocharis palustris subsp. vulgaris Walters (1949) is a later homonym of E. palustris var. vulgaris Čelak. (1867), so a replacement name, E. palustris subsp. waltersii, is proposed here. Eleocharis palustris var. vulgaris Čelak. is neotypified here with a modern specimen with 2n = 38, making it a taxonomic synonym of E. palustris subsp. waltersii or E. vulgaris “(Walters) Á. Löve et D. Löve”.

Lepší M., Vít P., Lepší P., Boublík K. & Suda J. (2008): Sorbus milensis, a new hybridogenous species from northwestern Bohemia. – Preslia 80: 229–244.
A new apomictic triploid (2n = 3x = 51) species belonging to the Sorbus latifolia group, S. milensis M. Lepší, K. Boublík, P. Lepší et P. Vít, putatively of hybridogenous origin between sexual Sorbus aria s.l. and S. torminalis, is described from the České středohoří Mts (northwestern Bohemia, Czech Republic). Several biosystematic techniques, including molecular (nuclear microsatellite markers), karyological (chromosome counts, genome size) and multivariate morphometrics were used to assess the variation in this species and justify its independent taxonomic status. The only known population of S. milensis consists of 38 adult and 19 juvenile individuals, is phenotypically homogenous and distinct from other Bohemian hybridogenous Sorbus species. All sampled individuals were karyologically uniform and showed little genetic variation. Sorbus milensis is a stenoendemic occurring on Milá hill (situated ca 9.5 km NNW of the town of Louny) where it grows on basaltic rocks, in ravines and on screes. The majority of the individuals grow in scree forests of the Tilio-Acerion alliance; other vegetation types include xeric scrub of the Prunion spinosae alliance and xerothermophilous grassland communities of the Festucion valesiacae alliance. A detailed distribution map for this species is provided as well as photographs of the type specimen.

Klimešová J., Latzel V., de Bello F. & van Groenendael J. M. (2008): Plant functional traits in studies of vegetation changes in response to grazing and mowing: towards a use of more specific traits. – Preslia 80: 245–253.
Plants’ abilities to function are difficult to evaluate directly in the field. Therefore, a number of attempts have been made to determine easily measurable surrogates – plant functional traits (PFTs). In particular, the value of PFTs as tools for predicting vegetation responses to management (i.e., grazing and mowing) is the focus of a large number of studies. However, recent studies using PFTs to predict the effect of pasture management in different regions did not give consistent predictions for the same set of PFTs. This lead to the suggestion that more specific traits better suited for a specific region be used in the future. We consider the identification of the most adaptative traits for surviving grazing and mowing in different biomes an important goal. Using temperate grasslands in Europe as an example, we show that (i) plant height, often considered as the best predictor of species response to grassland management, is coupled with other more relevant functional traits, and that (ii) clonal traits have important, often neglected functions in the response of species to grassland management. We conclude that single traits cannot be the only basis for predicting vegetation changes under pasture management and, therefore, a functional analysis of the trade-off between key traits is needed.

Klimešová J. & Klimeš L. (2008): Clonal growth diversity and bud banks of plants in the Czech flora: an evaluation using the CLO-PLA3 database. – Preslia 80: 255–275.
The CLO-PLA3 database includes data on vegetative growth relevant to clonality and vegetative regeneration for all (not only clonal) Central-European species. It consists of sheets, with each sheet based on a particular literature reference or our own morphological study documented by drawings. The data are interpreted according to a standardized protocol. The total number of sheets in the database is 7086. A total of 5818 sheets cover the flora of the Czech Republic representing 2775 taxa. Original drawings are available for 938 sheets. There are altogether 17 types of clonal growth organs (CGOs) used do describe morphology of iterative growth. Other clonal traits are the role of CGOs in the life cycle of the plant, shoot cyclicity, persistence of connections between ramets, number of offspring shoots per parent shoot per year, lateral spread per year, type of branching, tillering in graminoids, roots along the CGO, leaf distribution, size of offspring shoot, timing of CGO formation in ontogeny and overlap of shoot generations. Bud bank traits include vertical distribution of buds, their number per shoot and seasonality. Whole-plant traits include taproot persistence, reproduction type, storage organs, age at first flowering and genet life-span. An analysis of the CLO-PLA3 database for the flora of the Czech Republic revealed that plants with epigeogenous and hypogeogenous rhizomes are the most frequent among those growing clonally, followed by root-sprouters, non-clonal plants and plants with rooting above-ground stems. Other types of clonal growth organs like bulbs, stem and root tubers, bulbils, turions, plant fragments and budding are rare. A connection between clonal offspring shoots persisting for more than two years, a shoot longevity of one year, production of one offspring shoot per parent shoot per year and little lateral spread are prevailing trait values in the Czech flora. Seasonal bud banks prevail above ground, perennial bud banks occurmostly in the upper soil layer and the potential bud bank predominantly deeper than 10 cm below ground. From the analysis it follows that even if clonality is widespread in the Czech flora, the overall vegetative multiplication or spreading rates are low. The most common bud bank types reflect the fact that the majority of species in the Czech flora are perennial herbaceous plants.

Mácová M. (2008): Dendroclimatological comparison of native Pinus sylvestris and invasive Pinus strobus in different habitats in the Czech Republic. – Preslia 80: 277–289.
Many species of the genus Pinus are important forestry trees that escape from plantations and invade natural and seminatural habitats. This study compares the native Pinus sylvestris with an invasive alien P. strobus in the Czech Republic in terms of their radial growth response to climate. Pinus strobus invades sandstone regions, while in areas with another bedrock and soil type it regenerates only sparsely. The research was conducted in six areas differing in abiotic characteristics and the degree of P. strobus regeneration. The effect of climate on the diameter growth was studied using moving and evolutionary correlation and response function analyses. Climatic factors affect radial growth of both species; some reactions are species-specific, others are the same for both species but differ in their intensity. Pinus sylvestris responded positively to high February/March temperatures, P. strobus negatively to high temperatures and low precipitation in the previous September in all study sites. Both species responded to summer rainfall in warm and dry areas, but the response of P. strobus was stronger than that of P. sylvestris. In sandstone areas, both species responded to specific microsite conditions. The study did not find a clear link between dendroclimatological response of P. strobus and its invasive behaviour in sandstone areas of the Czech Republic.

Lososová Z. & Simonová D. (2008): Changes during the 20th century in species composition of synanthropic vegetation in Moravia (Czech Republic). – Preslia 80: 291–305.
Variation in species composition and proportion of different plant traits were studied for weed and ruderal vegetation in the eastern part of the Czech Republic (Moravia), especially the temporal changes from the beginning of the 20th century up to 2005. Data sets for 433 weed species and 695 ruderal species were used in the analysis. While historical data on the occurrence of synanthropic species were obtained from floristic literature, that on recent occurrence were extracted from the Czech National Phytosociological Database. Species that were common in the past are still common a century later and rare species are becoming rarer. Almost a quarter of all synanthropic species recorded at the beginning of the last century are endangered species and 12 are now extinct in this country. Some trends in species composition and particular species attributes were found. While mean abundance of archaeophytes and native species decreased, mean abundance of neophytes increased in both vegetation types during the last century. The use of regression tree models revealed that the relative abundance of weed and ruderal species is related to their species attributes, i.e. Ellenberg indicator value, lifespan, life strategy, pollination mode, plant height and flowering period. The most abundant weed species have always been shade-tolerant, relatively small plants that are able to flower for a long time and require high levels of nutrients. The most abundant weed species changed from insect-pollinated to those without any specific pollination mode. A long flowering period is an important attribute of the most abundant ruderal species. There was no significant change in ecological preferences of ruderal species. Regarding the life strategy of these species, CR-strategists were the most abundant in 1908 but less common in 2005 and partly replaced by C-strategists.

Jankovská V. & Pokorný P. (2008): Forest vegetation of the last full-glacial period in the Western Carpathians (Slovakia and Czech Republic). – Preslia 80: 307–324.
Palaeobotanical data from last full-glacial period in eastern-central Europe repeatedly confirm the existence of parkland landscapes with coniferous trees at relatively northern latitudes. However, up to now, the absence of fossils prevented a study of the full-glacial vegetation in the mountain areas of the Western Carpathians – a region crucial to determining whether there were refugia for present European forest biota during the Last Glacial period. This paper provides new pollen and macrofossil evidence from this key region, dated to a critical period in the Weichselian full glaciation (between 50 and 16 ka 14C BP). Our data from two study sites in the Western Carpathians (part of today’s Slovakia and easternmost Czech Republic – Moravian region) support the hypothesis that well-protected and relatively humid valleys in this mountain range were, as far as climate is concerned, favourable for forest vegetation during the last full-glacial period. These forests were similar to present Siberian coniferous taiga. In the lowlands and highlands that surround the Western Carpathians, there occurred a diversity of parkland landscapes: mosaic of steppe communities and tundra patches. However, we use the example of one site in central Bohemia, near what is the present city of Prague, to show that trees may also have occurred here on sites with a suitable local climate.

Ekrt L. & Štech M. (2008): A morphometric study and revision of the Asplenium trichomanes group in the Czech Republic. – Preslia 80: 325–347.
A detailed cytogeographic and morphometric study of the Asplenium trichomanes group in the Czech Republic is presented. We detected diploid (2n = 72), tetraploid (2n = 144) and hybrid triploid plants (2n = 108). Based on the morphometric study, four intraspecific taxa are recognized. These taxa correspond to the four subspecies of A. trichomanes (A. t. subsp. trichomanes, A. t. subsp. quadrivalens, A. t. subsp. pachyrachis and A. t. subsp. hastatum) distinguished in the floras of western, southern and northern Europe. Triploid plants were determined as A. t. nothosubsp. lusaticum (A. t. subsp. trichomanes × A. t. subsp. quadrivalens). The individual morphological characters used for determining subspecies are evaluated and a determination key presented.

Bastl M., Burian M., Kučera J., Prach K., Rektoris L. & Štech M. (2008): Central European pine bogs changing along an altitudinal gradient. – Preslia 80: 349–363.
Vegetation analyses (phytosociological relevés) of 20 peat bogs arranged along an altitudinal gradient in the southern part of the Czech Republic, Central Europe, revealed relationships between vegetation and environmental gradients. Six of the peat bogs were investigated in detail. The bogs were dominated by Pinus rotundata, a species endemic to Central Europe, and its hybridogenous populations with P. mugo (the hybrid is called P. ×pseudopumilio), with increasing proportions of the latter at higher altitudes. Data were processed using indirect (DCA) and direct (CCA) gradient analyses. Environmental variables (depth of the water table, mean and minimum temperatures, precipitation, pH, conductivity, NH₄ and PO₄ concentrations, total P, but not total N nor NO₃ concentration), as well as biotic characteristics of the sites, such as species composition, and growth form of the dominant pines, were closely correlated with altitude. Woody species, herbs and bryophytes responded to the altitude similarly. Results also indicated the unique characteristics of each bog.

Heinze B. (2008): Genetic traces of cultivated hybrid poplars in the offspring of native Populus nigra in Austria. – Preslia 80: 365–374.
Hybrid poplars like Populus ×canadensis or balsam poplar (Populus section Tacamahaca) hybrids have been propagated in Europe since the early 18th century. They replaced many stands of native black poplar on the banks of the major rivers. While spontaneous crosses between hybrid and native black poplars were not considered to be common or of importance in nature, it is shown that such crosses have occurred in Austria, as P. deltoides and section Tacamahaca alleles (PCR-amplified chloroplast and nuclear DNA markers) were found in plants morphologically similar to P. nigra. In the localities studied, a realistic estimate of the introgression rate is between 0 and 10% of plants in a given stand. Female hybrid trees produce viable seed. This shows that hybrid poplars can spread their genes by sexual means, which may result in continuing introgression and consequently, a reduction in genetic diversity and fitness of the endangered P. nigra.

Knapp S., Kühn I., Wittig R., Ozinga W. A., Poschlod P. & Klotz S. (2008): Urbanization causes shifts of species’ trait state frequencies. – Preslia 80: 375–388.
Urbanization is one of the most extreme forms of land transformation. It is supposed to change the frequencies of species trait states in species assemblages. We hypothesize that the flora of urban and rural areas differs in the frequency of trait states and ask which traits enable a plant to cope with the urban environment. We tested our hypothesis in Germany, which was divided into grid-cells of ca 130 km². We distinguished urbanized (with more than 33% urban land use; n = 59), agricultural (with more than 50% agricultural land use; n = 1365) and semi-natural (with more than 50% forest and semi-natural land use; n = 312) grid-cells and calculated the proportions of plant species per trait state in each grid-cell. Multiple linear regressions explained the log-transformed ratio of one proportion to another with land use (urban, agricultural, semi-natural) and the environmental parameters (climate, topography, soils and geology). Additionally, linear mixed effect models accounted for the effects of land use and biogeography and differences in sample size of the three grid-cell types. Urbanized and rural areas showed clear differences in the proportion of trait states. Urbanized grid-cells had e.g., higher proportions of wind-pollinated plants, plants with scleromorphic leaves or plants dispersed by animals, and lower proportions of insect-pollinated plants, plants with hygromorphic leaves or plants dispersed by wind than other grid-cells. Our study shows that shifts in land use can change the trait state composition of plant assemblages. Far-reaching urbanization might consequently homogenize our flora with respect to trait state frequency.

Štěpánková J. (2008): Carex derelicta, a new species from the Krkonoše Mountains (Czech Republic). – Preslia 80: 389–397.
A new species of the Carex flava complex (Cyperaceae) is described from the Czech Republic. It is known only from the type locality and is assumed to be endemic to the Krkonoše Mts. Its systematic position along with karyological and ecological notes are presented here. The new entity proposed, Carex derelicta, is included in the subsection Serotinae of the section Ceratocystis. The distinctive features of this species are its combination of globose to shortly cylindrical female spikes, glumes of female spikes equalling or exceeding the perigynia; perigynia 2.0–2.5 mm long, not inflated, vivid green, beaks 0.4–0.7 mm long and achenes completely filling perigynia. The chromosome number n = 35 is the first reported for this taxon.

Štechová T., Hájek M., Hájková P. & Navrátilová J. (2008): Comparison of habitat requirements of the mosses Hamatocaulis vernicosus, Scorpidium cossonii and Warnstorfia exannulata in different parts of temperate Europe. – Preslia 80: 399–410.
Habitat affinities of the red-listed and EU Habitat Directive moss species Hamatocaulis vernicosus and the more widely distributed allied species Scorpidium cossonii and Warnstorfia exannulata were analysed. Ecological preferences of these fen mosses, with respect to water pH, water conductivity, Ellenberg’s moisture and nutrient indicator values, were compared in three different European locations (Bohemian Massif, the West Carpathians and Bulgaria) using logistic regressions fitted by means of Huisman-Olff-Fresco models. Inter-specific co-occurrences of the species were also investigated. Warnstorfia exannulata preferred slightly acid conditions, about pH 5.6 at all the locations studied. Ecological behaviour of S. cossonii was very similar at all the locations, where it occupied base-rich habitats (pH > 7). The pH optimum of H. vernicosus, occupying habitats in the middle part of the base richness gradient, varied between locations from 6.0 in Bulgaria to 6.7–7.0 in the West Carpathians and Bohemian Massif. Niche diversification followed the gradient in Ellenberg nutrient indicator values and was similar at all the locations. In the Bohemian Massif and Bulgaria, the occurrence of W. exannulata was further associated with a relatively high moisture indicated by the Ellenberg indicator value. The results obtained from the Huisman-Olff-Fresco models accord with the results of inter-specific co-occurrences. Moreover, the latter method revealed a link between H. vernicosus and the occurrence of disjunctly occurring boreal sedges, suggesting the relic nature of H. vernicosus habitats at these locations.

Pellegrino G., Bellusci F. & Musacchio A. (2008): Double floral mimicry and the magnet species effect in dimorphic co-flowering species, the deceptive orchid Dactylorhiza sambucina and rewarding Viola aethnensis. – Preslia 80: 411–422.
Reproductive success of food-deceptive orchids may be affected by interactions with co-flowering rewarding species, either negatively through competition for pollinators, or positively by means of a magnet species effect and floral mimicry. In this study, potential interactions between a dimorphic (yellow or purple flowers) non-rewarding orchid Dactylorhiza sambucina and a dimorphic (yellow and blue flowers) rewarding, co-flowering species, Viola aethnensis, were explored in a natural stand in southern Italy. To evaluate the interactions between these two species, plots of all possible arrays of presence/absence of the four colour morphs were arranged in the field and fruit production of the orchid morphs assessed. Natural aggregations of both colour morphs of the orchid had the highest reproductive fitness for each colour morph. Patterns in fitness variation detected in treated plots provided direct and indirect evidence that D. sambucina may benefit from the co-occurrence of V. aethnensis through floral mimicry and/or magnet species effect. Since the fitness of each orchid morph was strongly increased by the presence of a viola morph of similar colour, a double mimetic effect occurs between the two species, which to our knowledge has not been previously reported. Moreover, the co-occurrence of an orchid morph with a non-matching viola resulted in competition for pollinators, whereas in the absence of the rewarding plant the fitness was balanced due to positive interactions between the two orchid colour morphs. These findings suggest that D. sambucina, like many other European deceptive orchids, possesses a set of display traits suitable for exploiting potential facilitative interactions with a number of rewarding species. In addition, the unequal morph frequencies occurring in natural populations could result from unbalanced events in floral mimicry.

Götzenberger L., Kühn I. & Klotz S. (2008): Effects of habitat disturbance and pollination type on the interspecific variation in pollen-ovule ratios. – Preslia 80: 423–437.
In this study two important factors that are thought to govern interspecific variation in pollen-ovule ratios were examined. First, the effect of habitat disturbance on variation in pollen-ovule ratio was determined. The second factor studied was the pollination type, used as a surrogate for the efficiency of pollination. Because seed mass is known to be strongly correlated with the pollen-ovule ratio it was also included in the analyses to examine if a possible effect of habitat disturbance or pollination type is still valid after accounting for the effect of seed mass. Furthermore, phylogenetically comparative methods were used to investigate whether the correlations between traits were maintained through evolutionary history or are only present in recent species data, i.e. in analyses that do not consider phylogenetic relationships between species. In conflict with the reproductive assurance hypothesis, habitat disturbance did not have a significant effect on interspecific pollen-ovule ratio variation. In contrast, pollination type accounted for a significant proportion of the variation in pollen-ovule ratios, even after taking into account the strong effect of seed mass. General results do not differ between the cross-species and phylogenetic comparative approaches. The results both accord with the predictions of the sex allocation theory and the proposition that the chance of a pollen grain reaching a stigma governs the pollen-ovule ratio.

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