Ecological differentiation of Central EuropeanBolboschoenus taxa and their relationship to plant communities

The taxa of theBolboschoenus maritimus group occurring in Central Europe were studied with respect to morphological differentiation, plant communities and soil conditions. Four morphological types ofBolboschoenus were distinguished, differing in habitat conditions, dispersal and distribution: type 1 —Bolboschoenus maritimus subsp.maritimus with narrow triangular fruits; type 2 —B. maritimus subsp.maritimus with wider triangular fruits, type 3 —B. maritimus subsp.compactus with round convex fruits; and type 4 —B. planiculmis auct. with concave fruits. Strong ecological differentiation of these types was found compared with relatively weak morphological diagnostic features. High discriminant efficiency appeared in the relationship to soil chemistry. Differences were also found in habitat-type spectra of individualBolboschoenus morphological types, which was reflected in their affinities to plant communities. Nomenclature, taxonomic classification, and distribution of these taxa in Europe need thorough revision.     

The genus Bolboschoenus in Iran: taxonomy and distribution

A revision of the Iranian Bolboschoenus was made based on studies of herbarium material and cultivated plants. Fruit features (fruit shape and pericarp anatomy) were used as the main distinguishing characters; style branching, inflorescence structure and the colour of floral scales were considered as accompanying distinguishing characters. The following taxa were recognized: Bolboschoenus glaucus (Lam.) S. G. Sm., B. affinis (Roth) Drobov, B. schmidii (Raymond) Holub, B. planiculmis (F. Schmidt) T. V. Egorova and B. maritimus (L.) Palla. Taxonomical difficulties, especially in the B. affinis group and B. maritimus are discussed. Bolboschoenus glaucus was found in all of the phytogeographical regions of Iran, and it is more frequent than any other Bolboschoenus species. Bolboschoenus planiculmis is very rare in the Irano–Turanian and Hyrcanian regions and grows only in human‐influenced habitats; it might be introduced as a weed in rice fields. Bolboschoenus maritimus, B. affinis and B. schmidii occur in the Irano–Turanian region only rarely. Bolboschoenus maritimus reaches the southeastern border of its distribution area in this region. All these species typically grow at higher altitudes. Great morphological variability in inflorescence structure was found in some species (especially in B. glaucus), which may be partly explained as a response to habitat conditions and partly by genotypic diversity.     

New chromosome numbers for plant taxa endemic to the Balearic Islands

Mitotic chromosome numbers are reported from 25 vascular plant taxa, endemic to the Balearic Islands that are poorly known cytogenetically. The chromosome numbers ofAnthyllis vulneraria subsp.balearica (2n=12),Cymbalaria fragilis (2n=56), andPolygonum romanum subsp.balearicum (2n=40) were determined for the first time. A new chromosome number was found in several populations ofAnthyllis hystrix (2n=70) suggesting that this species is decaploid, in contrast to an earlier work reporting a higher ploidy level (2n=12x=84). The new chromosome number 2n=32 was reported inHypericum hircinum subsp.cambessedesii. It is suggested that the previous count (2n=40) could be explained by the presence of anomalous pentaploid cells in some tissues, contrating with the presence of a regular tetraploid complement (2n=32). Cytogenetic observations suggest thatSibthorpia africana has a diploid chromosome complement of 2n=18, with 0–2 accessory chromosomes. Accessory chromosomes are also reported forPhlomis italica, being the first record of B chromosomes in this genus. Chromosomal instability was found inGalium crespianum andG. friedichii species, with three numbers 2n=44, 55 and 66. Two cytotypes differing in ploidy level were documented within single plants. It is suggested that both species share a regular complement of 2n=44 and that the past hybridization events and formation of regenerating roots from the typical rootstock ofG. crespianum andG. friedrichii could be involved in the genesis of chromosome variants through partial endopolyploidy and concomitant somatic segregation.     

Effect of anatomical structure on the buoyancy of achenes of two subspecies ofBolboschoenus maritimus

Differences between two subspecies ofBolboschoenus maritimus (L.)Palla (=Scirpus maritimus L.) in different habitats (littoral and terrestrial) are partly due to variations in the buoyancy of their achenes, caused by different anatomical structure of the fruits. This hypothesis was tested by comparing fruit buoyancy and anatomy of both subspecies at several localities. Plants were sampled fromBolboschoenus maritimus subsp.maritimus (plants with branched inflorescences and triangular fruits, 4 localities) andB. maritimus subsp.compactus (Hoffm.)Hejný (plants with compact inflorescences and prevailing concave fruits, 4 localities) in the Czech and Slovak Republics, andB. maritimus subsp.compactus (plants with compact inflorescences and convex fruits, 1 locality) from the coast of South Sweden. From each locality a plant with several tubers connected by rhizomes was taken and transferred into the experimental garden; from these cultivated plants (clones) mixed samples of fruits collected from each clone were used for buoyancy tests and a study of their anatomy. Fruit buoyancy was found to depend on the anatomical structure of the pericarp—the presence of aeriferous tissue in the exocarp serves as the main floating organ. This differentiated all plants studied into two groups: short-floating subsp.maritimus, with a thin or none acriferous tissue in the exocarp, and long-floating subsp.compactus with well developed aeriferous tissue. Differences in fruit buoyancy corresponds to differences in the prevailing habitat types of both subspecies studied in the inland sites: the frequent occurrence of subsp.compactus in temporarily flooded terrestrial habitats contrasts with the prevalence of subsp.maritimus in the littoral of water bodies. This is an example of intra-specific ecological differentiation leading to differentiation in wetland communities.     

Cytogeographical survey ofEleocharis subser.Eleocharis in Europe 1:Eleocharis palustris

Chromosome numbers forEleocharis palustris subsp.palustris (based on 70 samples from Austria, Bulgaria, Croatia, the Czech Republic, Germany, Greece, Hungary, Lithuania, Romania, Russia, Slovakia, Slovenia, and Sweden) andEleocharis palustris subsp.vulgaris (based on 74 samples from Austria, the Czech Republic, Denmark, Germany, Ireland, Latvia, Luxembourg, the Netherlands, Portugal, and Sweden) are given. Also the chromosome number estimates based on relative DNA contents of plants from 8 localitiesE. palustris subsp.palustris from Croatia, the Czech Republic, Germany, Italy, Israel, and Slovenia, and from 18 localities ofE. palustris subsp.vulgaris from the Czech Republic, Germany and Sweden are included. InE. palustris subsp.palustris, 2n=16 prevailed, the mixoploid 2n=15, 16 was rare and a lone hypoploid 2n=15 was detected. InE. palustris subsp.vulgaris 2n=38 was most frequently detected, the hyperploid 2n=39 and mixoploid 2n=38, 39 were common, and the hypoploid 2n=36 and mixoploids in which 2n ranges from 36 to 42 were rarer. Distribution maps based on plants investigated either by chromosome counting or by flow cytometry, augmented by similar data from published sources are given for both subspecies in Europe.     

Karyological studies in IberianSonchus (Asteraceae: Lactuceae): S. oleraceus, S. microcephalus andS. asper and a general discussion

Chromosome numbers and karyotypes ofSonchus oleraceus (n=16, 2n=32),S. asper (n=9, 2n=18 for subsp.asper and subsp.glaucescens, andS. microcephalus (n=15, 2n=30) are studied; for the first time their idiograms are given. Karyotypes mainly comprise small chromosomes with a degree of asymmetry 2B inS. oleraceus andS. microcephalus and 2A or 2A-2B inS. asper. No karyological differences can be pointed out betweenS. asper subspecies. Data presented support the amphiploid character ofS. oleraceus, and the origin ofS. microcephalus through a dysploid process involving the former taxon. In Iberian representatives of the genus, diagrams of karyotype asymmetry indices show a cluster grouping for species, with the detached exceptions ofS. maritimus andS. crassifolius, which spontaneously hybridize in central Spain. A review of available karyological data shows that in the evolution of the genusSonchus s.l. and relatives, the basic chromosome number x=9 has generally been maintained. Dysploidy is restricted to the seriesS. bourgeaui (n=8) —S. tenerrimus (n=7) andS. oleraceus (n=16) —S. microcephalus (n=15), evolutionarily related and included in the present subgenusSonchus. Polyploidy has been detected in a total of nine taxa ofSonchus and in the generaEmbergeria, Kirkianella, andDendroseris, being more common in peripheral regions of the distribution area of the group. Five diversification centers are proposed for the whole group, of which the Western Mediterranean area, including the Iberian Peninsula, is related to diversification of the present subgenusSonchus.     

Achene structure and taxonomy of North American Bolboschoenus (Cyperaceae)

Surface and transverse section achene structures ofBolboschoenus maritimus, B. robustus, B. fluviatilis, B. novae-angliae, B. glaucus, and the putative hybridsB. maritimus × B. rubustus andB. glaucus × B. maritimus from North America are described and illustrated with SEM micrographs. The same three type of pericarp structure reported by Browning and Gordon-Gray (1993) from southern Africa were found except that the “type 2” (B. glaucus) was not matched precisely. Intermediate achene structures and other evidence support both the hybrid origin ofB. novae-angliae (=B. fluviatilis × B. robustus) and hybridization betweenB. glaucus andB. maritimus. The new combinationBolboschoenus novae-angliae is made.     

Bolboschoenus glaucus (Lam.) S.G. Smith, a new species in the flora of the ancient Near East

Taxonomic advancement in the genus Bolboschoenus (Cyperaceae, formerly included in the genus Scirpus) have resulted in the re-classification of the plant previously known as Bolboschoenus maritimus (synonym Scirpus maritimus) into several closely-related but distinct Bolboschoenus species This improved taxonomy is of importance for archaeobotanical investigations of ancient sites within the temperate zones, where this genus frequently occurs, because it allows more precise definitions of the ecological requirements and growing habits of each species. Moreover, it details the distinct morphological and anatomical characteristics of the fruit (nutlets) of each species. Using these new nutlet classification criteria, we re-examined charred archaeological specimens which had previously been identified as B. maritimus (or S. maritimus), from five Near Eastern late Pleistocene and early Holocene village sites: Abu Hureyra, Hallan ?emi, Demirk?y, ?atalh?yük and Aswad. Because three of these sites are located in Anatolia, data on the recent occurrence of Bolboschoenus in Turkey were also investigated. All archaeobotanical specimens were found to be B. glaucus. This species was also found to be the most common Bolboschoenus in present-day Turkey, indicating that it has a long history of occurrence in this region. The environmental, ecological and economic implications of this new information suggest that it is entirely feasible that this plant provided late Pleistocene and Holocene Near Eastern people with a dependable and possibly a staple food source.     

Introgressive hybridization between a native and an introduced species:Viola lutea subsp.Sudetica versusV. Tricolor

A hybrid swarm betweenViola lutea subsp.sudetica (2n=50, native species) andViola tricolor (2n=26, introduced species) originated in the 1970’s in the Krkono?e Mts. Analyses of chromosome numbers, reproductive biology, morphology, and ecology gave the following results: (1) Compared to the plants found in the 1970’s, the number of colour morphs have decreased and the types now prevailing in the field are morphologically closer toV. lutea subsp.sudetica, forming a continuum. (2) In the field, hybrids having approximately the same chromosome number as the primary hybrids are most common. Some plants of the hybrid swarm have certain characters unknown to their parents. (3) In the field, autogamous types similar toV. tricolor were found. (4) A limited number of plants from the field and culture have higher somatic chromosome numbers thanV. lutea subsp.sudetica; there was a tendency towards increasing chromosome numbers in their progeny (up to 2n=62). These plants have some new morphological characters (a small proportion of hexacolpate pollen) not found in the parents (nor in the other hybrids with prevailing tetracolpate and pentacolpate pollen grains) and higher pollen fertility in comparison to the other hybrids. These plants also have the highest germination rate. (5) There is a tendency for chromosome numbers to decline in the progeny of open pollinated hybrid plants in the lowland experimental graden. (6) The phenology of the plants in the mountain grasslands and the lowland garden is different; the parents behave in a totally contrasting manner. (7) In the field at least some hybrids extend outside the geographical and ecological ranges of the parental species, invading new communities. (8) Seeds ofV. tricolor do not show any dormancy and germinate in the year of production; most of theV. lutea subsp.sudetica seeds germinate during the spring of the following year. Hybrids with intermediate chromosome numbers had both types of germination strategy. The germination rate of intermediates with high chromosome numbers was even higher than that ofV. tricolor.     

Chromosome number variability in central european members of the<Emphasis Type="Italic">Festuca ovina</Emphasis> and<Emphasis Type="Italic">F. pallens</Emphasis> groups (sect.<Emphasis Type="Italic">Festuca</Emphasis>)

Chromosome numbers for 98 plants ofF. pallens, 19 ofF. psammophila, F. belensis andF. vaginata, and 44 ofF. ovina (originating from Austria, the Czech Republic, Germany, Slovakia and Latvia) are given. In addition to theF. ovina andF. pallens groups, chromosome counts for the following taxa are also reported:F. alpestris (2n=14) reported for the first time in this work,F. amethystina subsp.amethystina (2n=28),F. brevipila (2n=42),F. cinerea (2n=28),F. rupicola subsp.rupicola (2n=42) andF. versicolor subsp.versicolor (2n=14).InF. pallens, two ploidy levels (2n=2x=14+0-1B, 2n=4x=28+0-1B) as well as two natural triploid plants (2n=21+0-1B), were found. In addition to the fourF. pallens types that have been distinguished in Austria, one new tetraploid type (F. pallens “scabrifolia”) from the Czech Republic and Germany is reported and its taxonomy is discussed. The distributions of the Oberösterreich-Niederösterreich and Pannonisches-HügellandF. pallens types outside of Austria are documented.Only the diploid chromosome number (2n=14) was found inF. psammophila andF. vaginata. Chromosome numbers forF. psammophila subsp.muellerstollii andF. belensis (both 2n=14) were determined here for the first time. Two ploidy levels, 2n=14+0-5B corresponding toF. ovina subsp.ovina and 2n=28 corresponding toF. ovina subsp.guestphalica andF. cf.duernsteinensis were confirmed inF. ovina. Differences in chromosome structure (simple and multiple secondary constrictions) betweenF. pallens as opposed toF. psammophila andF. vaginata are discussed. A complete survey of published chromosome counts for Central European species from theF. ovina andF. pallens groups is included.     

Karyosystematics ofVeronica sect.Beccabunga (Scrophulariaceae) with special reference to the taxa in Turkey

The chromosome numbers ofVeronica beccabunga subsp.abscondita (2n=18),V. anagallis-aquatica subsp.lysimachioides (2n=18),V. anagallis-aquatica subsp.michauxii (2n=36), and of a presumable hybridV. poljensis × V. anagalloides (2n=36) are new for the relevant taxa. — A new number was found forV. anagalloides subsp.heureka (2n=18). The other counts, ofV. scardica (2n=18),V. anagalloides subsp.anagalloides (2n=18), andV. anagallis-aquatica subsp.oxycarpa (2n=36) agree with earlier findings.—Data from the literature have been critically evaluated, in some cases the relevant vouchers have been checked and, where needed, the original determinations have been revised. For several taxa, comments concerning their systematics and remarks on their distribution in Turkey are given.     

Chromosome numbers of Mongolian Angiosperms. II.

Chromosome numbers are reported for 20 collections of Mongolian plants representing 19 taxa. The first chromosome records are reported forArabidopsis mongolica (2n=16),Caragana pygmaea (2n=16),Isatis costata var.leiocarpa (2n=28),Lophanthus chinensis (2n=18) andStevenia cheiranthoides (2n=32). Counts partly differing from those previously recorded are given forBatrachium trichophyllum subsp.trichophyllum (2n=32+0-2B, 36+6B),Cuscuta chinensis (2n=60),Dracocephalum fragile (2n=72) andErysimum flavum (2n=14). Chromosome numbers of the following taxa were confirmed:Astragalus monophyllus (2n=16),Erodium stephanianum (2n=16),Gastrolychnis apetala (2n=24),Geum aleppicum (2n=42),Linum baicalense (2n=18),Rorippa palustris (2n=32),Rubia cordifolia subsp.pratensis (2n=22),Schizonepeta multifida (2n=12),Tribulus terrestris (2n=36) andVicia cracca (2n=14). Taxonomic remarks onArabidopsis mongolia, Erysimum flavum, Stevenia cheiranthoides andVicia cracca are added. A new combinationArabidopsis mongolica (Botsch.)Měsí?ek & Soják is proposed.     

A high polyploidEleocharis uniglumis S.L. (Cyperaceae) from Central and Southeastern Europe

Chromosome counts and morphological measurements were carried out onEleocharis uniglumis s. 1. samples from nine populations in Slovakia, Hungary, Austria and Croatia. A high polyploidEleocharis uniglumis s.l. (2n=71–88) was found on halophilous sites: in western Slovakia (Svätojurský ?úr near Bratislava; 2n=71–78), on the Hungarian and Austrian shores of Lake Neusiedlersee (Hungary: Hidegség; Austria: Tadten, St. Andrä am Zicksee; 2n=71–82), and on the Croatian island of Krk, (shores of Lake Jezero and Lake Ponikve; 2n=80–88). These high polyploid populations have the same ploidy level asE. uniglumis subsp.sterneri, described as endemic to the islands of Öland and Gotland. Morphological similarities between the high polyploids and subsp.sterneri were found both in quantitative features correlated with ploidy level (stomatal length, anther length and fertile glume length) and in other characters (number of perianth bristles, broad sterile glume margins). Differences were detected in the receptacle density and in the length of perianth bristles compared to the length of the achene. Intermediate somatic chromosome numbers 2n=60–70, corresponding to Scandinavian hybrids betweenE. uniglumis subsp.uniglumis andE. uniglumis subsp.sterneri, were found near Neusiedlersee (Austria: Apetlon, Tadten; Hungary: Hidegség, Hegykö). These (karyologically intermediate) plants have intermediate stomatal lengths. In other features they are similar to the Central European high polyploids.Eleocharis uniglumis subsp.uniglumis (2n=46) was found here as well (Hungary: Fert?rákos).     

Chromosome numbers of severalLamiaceae from Spain

Chromosome numbers of twenty taxa, almost all of them Iberian endemics, of the generaTeucrium, Sideritis, Thymus andSalvia are reported. New chromosome numbers are given for the following taxa:Teucrium homotrichum (2n=78),T. hifacense (2n=26),T. rivasii (2n=26),T. rivas-martinezii (2n=26),Sideritis edetana (2n=30),S. murgetana subsp.littoralis (2n=28), and the hybridS. xviciosoi (2n=27). The first count on Iberian material forSalvia pratensis (2n=18) is reported. Chromosome numbers have been confirmed for the rest of the taxa studied on material from SE Spain. Karyotype analyses and taxonomic remarks are included.     

The allopolyploid origin ofSedum rupestre subsp.rupestre (Crassulaceae)

InSedum rupestre L. a polyploid series (x = 16) occurs in which aneuploid chromosome numbers and odd levels of ploidy prevail. The most common and widely distributed cytotype,S. rupestre subsp.rupestre, is 2n = 112. Plants resemblingS. rupestre subsp.rupestre can be obtained by hybridizing the tetraploid cytotypes ofS. forsterianum Sm. (2n = 48) andS. rupestre subsp.erectum 't Hart (2n = 64). Comparison of these artificial hybrids with their parents and a large number of plants ofS. rupestre subsp.rupestre (2n = 112) from nature showed thatS. rupestre subsp.rupestre and the artificial hybrids are morphologically indistinguishable, and intermediate betweenS. forsterianum andS. rupestre subsp.erectum. MorphologicallyS. rupestre subsp.rupestre is closer to subsp.erectum than toS. forsterianum. Chloroplast DNA restriction patterns ofS. rupestre subsp.rupestre, however, resembleS. forsterianum more closely. The combined results of the hybridization experiments, the analysis of the cpDNA restriction patterns, and the morphological variation indicate the allopolyploid origin ofS. rupestre subsp.rupestre. Natural hybrids inSedum (Crassulaceae) 4.     

Selected chromosome counts of the Czechoslovak flora I

Chromosome numbers of the following nine taxa of the Czechoslovak flora are given:Atriplex rosea L.,Cardamine resedifolia L.,Groenlandia densa (L.)Fourr.,Isoëtes lacustris L.,Lysimachia nemorum L.,Parnassia palustris L.,Phelipanche caesia (Rchb.) Soják,Rumex patientia L. subsp.patientia andSymphytum officinale L. s. str. A new chromosome number of 2n=80 is reported forRumex patientia L. subsp.patientia. Chromosome numbers of another five taxa are first reported from Czechoslovakia. Each of the ascertained chromosome counts is discussed with respect to hitherto known reports.     

Chromosome numbers and DNA ploidy levels of selected species ofHieracium s.str. (Asteraceae)

Chromosome numbers and /or ploidy levels are reported for 44 species and subspecies ofHieracium s.str. from the following European countries: Andorra, Austria, Bulgaria, Czech Republic, France, Italy, Montenegro, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland and Ukraine. The chromosome numbers/DNA ploidy levels ofH. bocconei (2n ～ 4x),H. bupleuroides subsp.leviceps (2n = 27),H. caesioides subsp.caesioides (2n = 27),H. basifolium (H. caesium agg., 2n = 36),H. plumbeum (H. caesium agg., 2n = 36),H. glaucum subsp.nipholepium (2n= 27),H.gouanii (2n = 18),H. gymnocerinthe (2n = 27),H. ramondii (2n = 27),H. recoderi (2n = 18),H. stelligerum (2n = 18), andH. tomentosum (2n = 18, 2n ～ 2x, 2n ～ 3x) were determined for the first time. New ploidy levels are reported forH. cerinthoides s.str. (2n = 27),H. humile (2n = 36), andH. tommasinianum (2n = 27).     

Competition in microcosm between a clonal plant species (Bolboschoenusmaritimus) and a rare quillwort (Isoetessetacea) from Mediterranean temporary pools of southern France

Bolboschoenus maritimus, a clonal species, is locally invasive in Mediterranean temporary pools where it threatens endangered rare plant species such as Isoetes setacea. The combination of management modifications (grazing) and of the progressive accumulation of fine sediments in the pools contributed to the establishment of competitive perennial plants such as B. maritimus. The competitive advantage of B. maritimus on I. setacea has been studied in controlled conditions. The goal of this experiment was to assess the role of environmental conditions in the output of the competition between Bolboschoenus and Isoetes, notably hydrology and soil richness. For this purpose, Isoetes was cultivated alone (three individuals/pot) and with Bolboschoenus (three individuals of both species). The experiment was run with five replicates on six types of sediment (gradient of richness in sand/silt/clay) combined with three hydrological treatments (flooded, wet. and dry). The competitive advantage of Bolboschoenus was measured as the ratio of the production of Isoetes in mixture versus monoculture. The results showed that Isoetes was always outcompeted by Bolboschoenus. However, the competitive advantage of Bolboschoenus on Isoetes, was more related to hydrology than to soil richness. The competitive advantage of Bolboschoenus was very high in wet and flooded conditions and very low in dry conditions. This situation may lead to the extinction, medium-term, of the populations of I. setacea. The introduction of ovine grazing or of cut back practices in temporary pools could reduce the B. maritimus biomass and help toward the conservation of I. setacea populations. Guest editors: B. Oertli, R. Cereghino, A. Hull & R. Miracle Pond Conservation: From Science to Practice. 3rd Conference of the European Pond Conservation Network, Valencia, Spain, 14–16 May 2008     

Efficiency of three halophyte species in removing nutrients from saline water: a pilot study

Saline wetlands may be well suited for purifying contaminated water from saline agriculture and aquaculture or from freshwater-based agriculture in areas subject to increased salinity. However, case studies on the nutrient removal efficiency of halophyte species are scarce, especially for temperate regions. Here we tested the nutrient removal efficiency and ability to store nutrients in aboveground and belowground biomass of three halophyte species, Aster tripolium, Bolboschoenus maritimus subsp. compactus, and Spartina anglica, in a greenhouse microcosm experiment at two salinity levels. Nutrient removal from water differed among the species: Spartina had the highest nitrogen removal, Bolboschoenus and Spartina had the highest phosphorus removal. The species also differed in the allocation of the nutrient uptake. Bolboschoenus had the highest absolute uptake of nitrogen and phosphorus in shoots, whereas Spartina had the highest uptake of nitrogen and phosphorus in roots. The applicability of these three species in constructed saline wetlands depends on the local salinity and water regime.     

Cytogenetic studies on natural intergeneric hybridization inAster alliances

In addition to various types of natural hybrids betweenAster ageratoides subsp.ovatus andKalimeris incisa reported earlier, a new backcross type has been discovered. This new type, characterized by the chromosomes of 2n=27L+54S, was most probably produced through fertilization of a normally-reduced gamete of the F₁ plant (2n=72=18L+54S) and an unreduced gamete of subsp.ovatus (2n=36=18L+18S).