Copyright © Czech Botanical Society

Abstracts of volume 77, 2005

Trávníček B. & Zázvorka J. (2005): Taxonomy of Rubus ser. Discolores in the Czech Republic and adjacent regions. – Preslia 77: 1–88.
The current state of the taxonomy of Rubus ser. Discolores in the Czech Republic is summarized. Since 1995, when the group was treated in the Flora of the Czech Republic (Holub 1995), six new species have been recognized, some of which are also known from adjacent areas. They are described in the present study: R. austroslovacus Trávníček, R. flos-amygdalae Trávníček et Holub, R. guttiferus Trávníček et Holub, R. parthenocissus Trávníček et Holub, R. pericrispatus Holub et Trávníček and R. portae-moravicae Holub et Trávníček. The first five belong to the group of triploid species close to R. montanus Lej. and R. grabowskii Weihe, whilst R. portae-moravicae is related to R. praecox Bertol. Two additional species, originally recognized under provisional names, were found to be identical to species described earlier: R. perperus H. E. Weber and R. phyllostachys P. J. Mueller; the latter is also found in Slovakia. At present, 17 indigenous species, one naturalized alien (R. armeniacus Focke) and one rare garden escape (R. ulmifolius Schott) of the ser. Discolores are known to occur in the Czech Republic. Distribution data and a key for the identification of all the species are presented.

Botta-Dukát Z., Chytrý M., Hájková P. & Havlová M. (2005): Vegetation of lowland wet meadows along a climatic continentality gradient in Central Europe. – Preslia 77: 89–111.
Central European lowland wet meadows are habitats of great conservation interest, however, their phytosociological status has been to a large extent dependent on specific phytosociological traditions in different countries. In order to bridge the gaps between different national schemes of vegetation classification, a statistical analysis of variation in species composition of these meadows in the Czech Republic, E Austria, Slovakia, Hungary and NE Croatia was performed, using a data set of 387 geographically stratified vegetation relevés sampled at altitudes < 350 m. Principal coordinates analysiswas used to identify and partial out the noise component in the variation in this data set. The relevés were classified by cluster analysis. A new method for identifying the optimal number of clusters was developed, based on species fidelity to particular clusters. This method suggested the optimum level of classification with three clusters and secondary optimum levels with five and nine clusters. Classification based on three clusters separated the traditional phytosociological alliances of Calthion palustris and Molinion caeruleae, both with a suboceanic phytogeographical affinity, and a group of flooded meadows of large river alluvia, with a continental affinity. The latter group included the traditional alliances of Agrostion albae, Alopecurion pratensis, Cnidion venosi, Deschampsion cespitosae and Veronico longifoliae-Lysimachion vulgaris; however, the internal heterogeneity of this group did not reflect putative boundaries between these alliances as proposed in the phytosociological literature. Therefore we suggest to unite these alliances in a single alliance Deschampsion cespitosae Horvatić 1930 (the oldest valid name). Classification with nine clusters was interpreted at the level of broad phytosociological associations. Particular clusters were characterized by statistically defined groups of diagnostic species and related to macroclimatic variables.

Pokorný P. (2005): Role of man in the development of Holocene vegetation in Central Bohemia. – Preslia 77: 113–128.
In the subcontinental, semiarid lowland region of Central Bohemia (Czech Republic), continuous human impact acting together with diverse natural environmental conditions resulted in the present extraordinarily complex pattern of vegetation. Three radiocarbon-dated pollen diagrams for the area indicate that this complexity results from past vegetation development. During prehistory, places suitable for settlement (with respect to climate, geology, hydrology, etc.) were colonized and transformed first. This resulted in a diachrony in vegetation development due to human activity starting in the first half of the Holocene. This caused an increase in diversity in the region as plant species persisting from previous periods, along with those associated with different agricultural practices, increased. Local abiotic factors affected not only the chronology of human impact but also its specific effects on the ecosystem. Anthropogenic pressure may have had different effects under different conditions. Human population pressure was the mediator between the abiotic diversity and selectively transformed vegetation suitable for the respective habitats. Differences in the chronology of human impact, mixed oak woodland degradation, and the chronology of beech, silver fir and hornbeam expansion are documented for the different ecological zones of the study area. These differences shed light on the mechanisms resulting in some of the important changes in Holocene vegetation. In the absence of man, the decline in mixed oak woodlands, typical of the Middle Holocene in Central Bohemia, would have been probably much slower and less extensive. Unlike in the uplands and mountains, the expansion in the area of beech, silver fir and hornbeam would have been insignificant. The present vegetation resulted to a large extent from management during High Middle Ages. There is almost no continuity in vegetation from the late prehistory to the present.

Řepka R. & Danihelka J. (2005): Typification of the name Carex muricata var. lamprocarpa Wallr. and its nomenclatural consequences. – Preslia 77: 129–136.
The name Carex muricata subsp. lamprocarpa “Čelak.” (1879) is frequently used in floras for C. pairae F. W. Schultz when it is treated as a subspecies of C. muricata L. However, the combination C. muricata var. lamprocarpa was published by Wallroth in 1822. The corresponding specimen in Wallroth’s collection in PR, studied by L. Čelakovský and designated here as a lectotype, is C. muricata as it has the characteristic shiny utricles. So the combination C. muricata subsp. pairae (F. W. Schultz) Čelak. (1870) has to be used.

Ruprecht E. (2005): Secondary succession in old-fields in the Transylvanian Lowland (Romania). – Preslia 77: 145–157.
The main trends in spontaneous regeneration were studied in old-fields in the Transylvanian Lowland (Câmpia Transilvaniei) over a period of 40 years using the chronosequence method. Succession proceeds to grassland, because the establishment of woody vegetation is hindered by grazing and mowing of the old- fields and by the scarcity of woodlands in the vicinity. Community properties and population-level changes were recorded at different stages of succession and compared with semi-natural grassland in the surrounding landscape. Due to favourable soil conditions and temperate climate, vegetation cover develops quickly after the fields are abandoned. Annuals dominated only in the first year. After two years the fast growing clonal grass, Elymus repens, became dominant. After approximately 12 years, Elymus was replaced by Festuca rupicola, which is more resistant to stress and disturbance. In the later stages of succession various species, some typical of surrounding grassland, attained high cover values. A steady increase in species diversity, measured by the Shannon index, and richness was recorded at both the field (1.0–2.5 ha) and plot (4 × 4 m) scales. Species richness increased rapidly in early and middle stages and stabilized after the 14th year. Specific features of the succession in the old-fields in the Transylvanian Lowland can be attributed to the continued grazing and mowing of the fields after they are abandoned. This increases species richness because it arrests succession at a stage when species diversity is high. The management directs regeneration towards secondary grassland rather than species poor woodland.

Marhold K., Jongepierová I., Krahulcová A. & Kučera J. (2005): Morphological and karyological differentiation of Gymnadenia densiflora and G. conopsea in the Czech Republic and Slovakia. – Preslia 77: 159–176.
Gymnadenia densiflora was recently either misinterpreted or not accepted as a distinct taxon by several authors. To resolve its taxonomic position and differentiation from the related G. conopsea, a detailed study of the morphology, chromosome numbers and distribution of these two taxa in the Czech Republic, Slovakia and neighbouring areas was carried out. Chromosome counts showed an invariable diploid chromosome number (2n = 40) for G. densiflora, while G. conopsea is diploid, tetraploid and rarely also pentaploid (2n = 40, 80, 100). Results of morphometric analyses (principal component analysis, cluster analysis, classificatory and canonical discriminant analysis) confirmed a good morphological separation between G. densiflora and G. conopsea. Characters such as the width of the second lowermost leaf, height of the plant, number of flowers in the inflorescence, number of leaves, and the ratio of height of the plant and distance from the stem base to the base of the uppermost sheathed leaf contributed most to this separation. Our study supports the recognition of G. densiflora as a distinct species.

Rotreklová O., Krahulcová A., Mráz P., Mrázová V., Mártonfiová L., Peckert T. & Šingliarová B. (2005): Chromosome numbers and breeding systems of some European species of Hieracium subgen. Pilosella. – Preslia 77: 177–195.
Chromosome numbers (ploidy levels) were recorded in the following 25 taxa of Hieracium subgen. Pilosella: H. arvicola Nägeli et Peter (2n = 45), H. aurantiacum L. (2n = 36, 45), H. bauhini Besser (2n = 36, 45), H. bifurcum M. Bieb. (2n = 45), H. brachiatum Bertol. ex DC. (2n = 36, 45), H. caespitosum Dumort. (2n = 36), H. cymosum L. (2n ~ 4x), H. densiflorum Tausch (2n = 36, ~ 4x), H. echioides Lumn. (2n = 18, 45), H. fallacinum F. W. Schultz (2n = 36, 45), H. floribundum Wimm. et Grab. (2n = 36, ~ 4x, 45,), H. glomeratum Froel. in DC. (2n = 45), H. iseranum Uechtr. (2n = 36), H. kalksburgense Wiesb. (2n ~ 5x), H. lactucella Wallr. (2n = 18), H. macranthum (Ten.) Ten. (2n = 18), H. onegense (Norrl.) Norrl. (2n = 18), H. pilosella L. (2n = 36, 45, 54), H. piloselliflorum Nägeli et Peter (2n = 45), H. pilosellinum F. W. Schultz (2n = 36, 45), H. piloselloides Vill. (2n = 27, 36, ~ 4x, 45, ~ 5x), H. pistoriense Nägeli et Peter (2n = 27), H. rothianum Wallr. (2n ~ 3x), H. schultesii F. W. Schultz (2n = 36, 45, ~ 5x), H. zizianum Tausch (2n = 27, 36, 54), and one hybrid, H. onegense × H. pilosella (2n = 36). Besides chromosome counts in root-tip meristems, flow cytometry was used to determine the DNA ploidy level in 83 samples of 9 species. The presence of a long marker chromosome was confirmed in tetraploid H. caespitosum and H. iseranum, in pentaploid H. glomeratum, and in both tetraploid and pentaploid H. floribundum. The documented mode of reproduction is sexual (H. densiflorum, H. echioides, H. piloselloides) and apomictic (H. brachiatum, H. floribundum, H. pilosellinum, H. piloselloides, H. rothianum, H. zizianum). Hieracium bifurcum and H. pistoriense are sterile. The chromosome number and/or mode of reproduction of H. bifurcum (almost sterile pentaploid), H. pilosellinum (apomictic pentaploid), H. piloselloides (apomictic triploid), H. pistoriense (sterile triploid), H. rothianum (apomictic triploid) and H. zizianum (apomictic triploid) are presented here for the first time. The sexual reproduction recorded in the pentaploid H. echioides is the second recorded case of this mode of reproduction in a pentaploid cytotype of Hieracium subgenus Pilosella. A previously unknown occurrence of H. pistoriense (H. macranthumH. bauhini) in Slovakia is reported.

Vašut R. J., Štěpánek J. & Kirschner J. (2005): Two new apomictic Taraxacum microspecies of the section Erythrosperma from Central Europe. – Preslia 77: 197–210.
Two new species, Taraxacum maricum and Taraxacum cristatum, of the section Erythrosperma from Central Europe are described in this paper. These species are similar to western European taxa, T. maricum to T. proximum, and T. cristatum is morphologically close to T. scanicum. Both new taxa are triploid apomictic microspecies. Specific characteristics, information on distribution and ecology and comparison with similar species are presented. Pictures and distribution maps of the new species are also included.

Komárek J. (2005): Studies on the cyanophytes (Cyanobacteria, Cyanoprokaryota) of Cuba 11. Freshwater Anabaena species. – Preslia 77: 211–234.
Nineteen traditional Anabaena morphospecies were found in freshwater habitats in Cuba. Their taxonomic identification is discussed and variation in natural populations described. Seven species are known only from tropical countries (A. ambigua, A. fuellebornii, A. iyengarii, A. oblonga, A. orientalis, A. recta, A. volzii), four from tropical America (A. manguinii, A. portoricensis, A. torques-reginae, A. unispora), one was originally described from southern Africa (A. austro-africana) and one from central Asia (A. turkestanica). Two taxa are recognized as new species (A. hatueyi, A. jeejiae) and two remain unidentified (Anabaena spp.) because of a shortage of material. Only two species, A. cf. reniformis and A. cf. bornetiana, may occur also in the temperate zone (Europe or North America) and as special morphotypes in Cuba.

Roleček J. (2005): Vegetation types of dry-mesic oak forests in Slovakia. – Preslia 77: 241–261.
Typology of dry-mesic oak forest vegetation of Slovakia is presented. Seven vegetation types were distinguished based on a Braun-Blanquetian relevé data analysis using a TWINSPAN classification algorithm. The identified vegetation types are related to seven syntaxa traditionally used by Central European phytosociologists: dry-mesic oak forest on sandy soils – Carici fritschii-Quercetum roboris, dry-mesic oak forest on heavy soils – Potentillo albae-Quercetum, dry-mesic oak forest on basic rocky substrates – Corno-Quercetum, dry-mesic oak forest on acidic substrates – Sorbo torminalis-Quercetum, dry oak forest on loess – Quercetum pubescenti-roboris, dry-mesic oak forest on loess – Convallario-Quercetum roboris, dry-mesic forest of Turkey oak – Quercetum petraeae-cerris. Detrended correspondence analysis was used to visualize the similarity of vegetation types. Some aspects of dry-mesic oak forest ecology, distribution and dynamics in Slovakia are discussed; their general retreat due to mesophilous tree species expansion is stressed.

Kirschner J. & Štěpánek J. (2005): Dandelions in Central Asia: Taraxacum sect. Suavia. – Preslia 77: 263–276.
On the basis of the authors’ collections and cultivated material from Asia, a recently described group of dandelions, Taraxacum sect. Suavia, is revised. In addition to three species described previously (T. haneltii, T. sumneviczii and T. formosissimum), six new species from Mongolia and Kyrgyzstan are recognized. Three of them, T. suave, T. stupendum and T. margaritarium, possess most of the features characterizing the section Suavia, one, T. suasorium, is regarded as intermediate between sections Suavia and Leucantha, whilst the remaining two, T. nobile and T. venustius, exhibit some characters of another related section (T. sect. Stenoloba). The members of the section Suavia are agamospermous. Detailed descriptions, drawings and an identification key are given.

Jarolímová V. (2005): Experimental hybridization of species in the genus Rorippa. – Preslia 77: 277–296.
Experimentally produced interspecific hybrids between four Central European species of Rorippa (Brassicaceae), which are wide-spread in the Czech and Slovak Republics (allogamic R. amphibia, R. austriaca, R. sylvestris and autogamic R. palustris), were studied. The hybrid between the allogamic tetraploid species R. amphibia and R. sylvestris can produce hybrid swarms when they occur sympatrically with the parental species. The most plausible mode of formation of the tetraploid hybrid swarms introgressed by diploid R. austrica in nature was confirmed: The chromosome numbers of the offspring resulted from the controlled pollination of the triploid experimental hybrid R. austriaca × R. sylvestris mostly tended to the tetraploid level. Even healthy tetraploid plants, with high quality pollen, developed in the second generation after open pollination of the experimental triploid R. amphibia × R. austriaca. Plants with nearly tetraploid or tetraploid chromosome numbers and sufficiently fertile pollen gave rise to fully fertile tetraploid hybrid swarms, even without the presence of tetraploid R. austriaca. Failure of most experimental crosses of the autogamous tetraploid R. palustris with allogamous species (totally sterile F1 acquired only in combination R. austriaca × R. palustris) indicated that this species is unlikely to have participated in the formation of hybrid swarms in nature.

Krahulec F., Kaplan Z. & Novák J. (2005): Tragopogon porrifolius × T. pratensis: the present state of an old hybrid population in Central Bohemia, the Czech Republic. – Preslia 77: 297–306.
A population of a hybrid between Tragopogon porrifolius and T. pratensis (T. ×mirabilis), which occurs in SW part of the town of Roudnice nad Labem, N part of Central Bohemia, was analysed with respect to its morphology, fertility, life history, ploidy level and DNA content. Both parental species vary relatively little morphologically; they are biennials (monocarpic perennials) and diploids. T. pratensis is a native species in the Czech Republic, T. porrifolius was cultivated there in the past. The hybrid plants are extremely morphologically variable, with variation ranges of some characters overlapping those of the parental species (e.g. ligules are often longer than involucral bracts, peduncles are often lanate). Only diploids were found within the hybrid population; however, they have substantially lower DNA content than both parents (18% lower than T. pratensis, 42% lower than T. porrifolius). The plants of the Roudnice hybrid population are polycarpic perennials in contrast to the monocarpic perennial (mostly biennial) parents. The distribution is described in detail; it shows that the hybrid plants are spreading and at present even occur outside the town. The long-persisting population of fertile diploid hybrid plants in Roudnice nad Labem is an alternative evolutionary pathway to that of the allotetraploid Tragopogon species known from North America.

Peckert T., Chrtek J. jun. & Plačková I. (2005): Genetic variation in agamospermous populations of Hieracium echioides in southern Slovakia and northern Hungary (Danube Basin). – Preslia 77: 307–315.
Six populations of Hieracium echioides subsp. echioides var. tauscheri from the Danube Basin between Bratislava and Budapest (locations: Balinka, Čenkov, Devín, Dorog, Győr, Pilis) were analysed using allozyme and karyological analysis. Five allozyme systems (EST, LAP, 6PGDH, PGM, and SKDH) were used to analyse the genetic structure of the examined populations. Analyses revealed low genetic variation both within- and among populations. Four multilocus allozyme phenotypes were detected; three populations (Čenkov, Devín and Győr) possessed phenotype I exclusively, while phenotype II was found only in the Balinka and Dorog populations. Two different phenotypes were found in the population of Pilis (phenotypes III and IV). However, due to the complex banding patterns generated for EST, allelic interpretationwas not possible, and the Balinka and Dorog populations appeared to possess different phenotypes. All populations proved to be tetraploid (2n = 36) and agamospermous. The geographic distribution pattern of the analysed populations (one allozyme phenotype at several isolated localities) may reflect a more common occurrence of the taxon in the past. Landscape changes, caused by changes in human management of the country, may have resulted in a loss of suitable localities, mainly open sandy habitats. These changes may have caused the reduction and fragmentation of H. *tauscheri habitat.

Kochjarová J. (2005): Scilla bifolia group in the Western Carpathians and adjacent part of the Pannonian lowland: annotated chromosome counts. – Preslia 77: 317–326.
The chromosome numbers of 95 populations of taxa belonging to the Scilla bifolia group growing in the territory of Western Carpathians, and adjacent part of the Pannonian lowland (Slovakia, Hungary, Austria, Czech Republic – Moravia) are presented. Scilla kladnii Schur (41 populations) and S. vindobonensis Speta (18 populations) have only the chromosome number 2n = 18. Both these diploid taxa seem to be karyologically uniform throughout their distribution. For S. drunensis (Speta) Speta subsp. drunensis (2 populations), and S. drunensis subsp. buekkensis (Speta) Kereszty (15 populations) the chromosome number 2n = 36 was found. For S. spetana Kereszty (2 populations), the chromosome number 2n = 54 was confirmed for Hungary and Austria. For two groups of populations of S. drunensis s.l. from Slovakia (14 populations in total) the chromosome number is 2n = 36, which is new information for the Western Carpathians. Apart from tetraploids, hexaploid populations with 2n = 54 were confirmed for three localities in Slovakia and Czech Republic (Moravia). All results are compared with earlier published data.

Chytrý M., Pyšek P., Tichý L., Knollová I. & Danihelka J. (2005): Invasions by alien plants in the Czech Republic: a quantitative assessment across habitats. – Preslia 77: 339–354.
Occurrence of alien plant species in all the major habitats in the Czech Republicwas analysed using a data set of 20,468 vegetation plots, classified into 32 habitats according to the EUNIS classification. The plots contain on average 9.0% archaeophytes and 2.3% neophytes; for neophytes, this proportion is much smaller than 26.8% reported for the total flora of the country. Most neophytes are found in a few habitats: only 5.6% of them were recorded in more than ten habitats. By contrast, archaeophytes, and especially native species, tend to occur in a broader range of habitats. Highest numbers of aliens were found on arable land, in annual synantropic vegetation, trampled habitats and anthropogenic tall-forb stands. These habitats contain on average 22–56% archaeophytes and 4.4–9.6% neophytes. Neophytes are also common in artificial broadleaved forestry plantations; they also tend to make up a high percentage of the cover in wet tall-forb stands, but are represented by fewer species there. Entirely or nearly free of aliens are plots located in raised bogs, alpine grasslands, alpine and subalpine scrub and natural coniferous woodlands. Correlations between the number of archaeophytes or neophytes and the number of native species, calculated with habitat mean values, were non-significant, but there was a positive correlation between the numbers of archaeophytes and neophytes. The ratio of archaeophytes to neophytes was high in semi-natural dry and mesic grasslands and low in disturbed habitats with woody vegetation, such as artificial broadleaved forestry plantations, forest clearings and riverine willow stands. When individual plots were compared separately within habitats, the relationships between the number of archaeophytes, neophytes and native species were mostly positive. This result does not support the hypothesis that species-rich communities are less invasible, at least at the scale of vegetation plots, i.e. 100–102 m2.

Kanz B., Dürhammer O. & Printzen C. (2005): Lichens and lichenicolous fungi of the Bavarian Forest. – Preslia 77: 339–354.
A checklist of lichens and lichenicolous fungi reported from the German part of the Bohemian Forest Range (the Bavarian Forest) is presented together with the literature sources. The area covered by the checklist is region 37 circumscribed by Grummann (1963). The list comprises 867 species currently accepted as occurring within the area. A further 44 species have been reported from the area, but their occurrence is regarded as doubtful. Seventy-seven mostly infraspecific taxa from 19th century literature sources could not be assigned to any currently accepted name and are listed separately. An overlooked, historical record of Pyxine sorediata (Ach.) Mont. is reported as the first and only German record of this species. A linear increase in the number of reported species, with no sign of saturation in recent years, indicates that the lichen flora of the region is still incompletely known. The biogeographic composition of the lichen flora broadly reflects the climatic conditions within the study area. A significantly higher proportion of northern elements among terricolous lichens could indicate a high proportion of glacial relict species within this group. Because of the incomplete floristic inventory and limited distributional data for lichens in general, these conclusions should be viewed with caution.

Navrátilová J. & Navrátil J. (2005): Vegetation gradients in fishpond mires in relation to seasonal fluctuations in environmental factors. – Preslia 77: 405–418.
The composition of the vegetation of fishpond mires in the Třeboň Basin (Czech Republic) was studied in relation to temporal fluctuations in certain environmental factors. The water-table depth, water pH and electrical conductivity at 49 permanent plots were measured at approximately threeweek intervals from March to October 2003. Minimum, maximum, mean, median and variation in the above-mentioned environmental factors were correlated with vegetation composition. The most important environmental factors explaining the variation in vegetation were mean pH and maximum water-table level. Median conductivity increased with increase in waterlogging and eutrophication. Some seasonal trends in the dynamics of these parameters were observed. The lowest conductivity was in spring, increased continuously throughout summer and peaked in autumn. In contrast, water level decreased in summer, when evapotranspiration was greatest, and rose in autumn after heavy rainfall. The pH increased from March to June, then was stable and decreased at the end of summer. Seasonal trends were generally identical in all vegetation types. The fluctuations in the environmental factors were so considerable that they may influence the reliability of vegetation environmental analyses.

Kaplan Z. (2005): Potamogeton schweinfurthii A. Benn., a new species for Europe. – Preslia 77: 419–431.
The occurrence in the Mediterranean part of Europe of the African species Potamogeton schweinfurthii is recorded for the first time. So far, this native but overlooked species has been found on five major Mediterranean islands: Corsica, Sardinia, Malta, Kefallinía (Ionian Islands, Greece) and Crete. The species is most similar and presumably closely related to the mainly Eurasian P. lucens, with which it has been partly confused. The nomenclature and a description of P. schweinfurthii are provided, and its taxonomy and how it differs from similar taxa discussed. All known localities are listed, together with voucher specimens preserved in the major European herbaria. A distribution map of P. schweinfurthii in the Mediterranean region is presented.

Žíla V. & Weber H. E. (2005): A new species of Rubus from Bavaria, Bohemia and Austria. – Preslia 77: 433–437.
Rubus perpedatus Žíla et H. E. Weber (sect. Rubus ser. Radula Focke) is described as a new species. It differs from R. radula Weihe in having distinctly pedate leaves, terminal leaflets with an emarginate base, longer pedicels with longer stalked glands and with many more prickles. It is distributed in the Bavarian Forest, the Bohemian Forest and in Upper Austria. An illustration, a list of herbarium specimens and a map showing the distribution of this new species are provided.

Neustupa J. & Hodač L. (2005): Changes in shape of the coenobial cells of an experimental strain of Pediastrum duplex var. duplex (Chlorophyta) reared at different pHs. – Preslia 77: 439–452.
The changes in shape of the marginal coenobial cells in an experimentally cultured population of Pediastrum duplex Meyen var. duplex were investigated. The methods of landmark-based geometric morphometrics, including sliding landmarks registration, were used. The populations were cultured at 11 different pH levels and the changes in shape related to pH were studied using multivariate regression. The results of relative warps analysis revealed that morphological trends are related to both size and pH. The potential application of the results of this geometric morphometrical analysis of Pediastrum for biomonitoring and palaeoecological studies are discussed.

Nováková S. (2005): Pseudocarteria corcontica, a new quadriflagellate species (Volvocales). – Preslia 77: 453–457.
A new species Pseudocarteria corcontica is described from small, acidic and oligotrophic water bodies in the Krkonoše Mts (Czech Republic). The cells are 17–27 × 22–35 µm in size, ellipsoidal or obovate and with a low truncate papilla. The thick cell wall is sometimes separated from the protoplast at the posterior end of the cell. The chloroplast is indistinctly asteroid with an ellipsoidal or half-ellipsoidal pyrenoid located below the centre of the cell. Numerous contractile vacuoles are not scattered as in other Pseudocarteria species, but mostly concentrated in the upper third of the cell and form circle beneath the cell wall. A small elliptical stigma is located in the anterior part of the cell. Cells divide in immobile sporangia (up to 38 µm in diameter) producing 2 or 4 daughter cells. Sexual reproduction is isogamic.


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