Prvotní příčinou podivuhodného složení hadcové flóry jsou zvláštní chemické a fyzikální vlastnosti samotného hadce, které se však projevují v různé míře v závislosti na místních klimatických a geomorfologických podmínkách. Extrémní podmínky substrátu a izolovanost hadcových oblastí, které jsou u nás roztroušeny po celé republice, mohly vést až k evoluci hadcových (sub)endemitů. and The primary reason for the special composition of serpentine flora are the special chemical and physical features of the serpentine itself, whose expression differs according to local climatic and geomorphological conditions. The extreme condition of the substrate and the isolation of serpentine areas, dispersed across the whole country in the Czech Republic, can subsequently lead to the evolution of serpentine (sub)endemic species.
Článek je zaměřen na systematiku, evoluci, ekologii a možné příčiny ohrožení čtyř hadcových subendemitů ČR. Zatímco chrastavec rolní hadcový (Knautia arvensis subsp. serpentinicola) a mochna Crantzova hadcová (Potentilla crantzii subsp. serpentini) jsou poměrně dobře definované poddruhy, hvozdík kartouzek hadcový (Dianthus carthusianorum subsp. capillifrons) a trávnička obecná hadcová (Armeria vulgaris subsp. serpentini) jsou možná taxonomicky heterogenní jednotky, které spojuje pouze výskyt na hadcovém substrátu. Přesto však hadcové populace těchto druhů představují významný ekologický a fytogeografický prvek středoevropské flóry. and The article describes the possible reasons why four of the Czech serpentine subendemic species are endangered, as well as their systematics, evolution and ecology. While Knautia arvensis subsp. serpentinicola and Potentilla crantzii subsp. serpentini are relatively well defined subspecies, Dianthus carthusianorum subsp. capillifrons and Armeria vulgaris subsp. serpentini might be heterogeneous units having only the distribution on a serpentine substrate in common. Nevertheless, serpentine populations of these species are an important ecological and phytogeographical phenomenon among Central European flora.
Oba taxony s podobnou evoluční historií jsou dlouhodobě uznávanými endemity českých hadcových substrátů a nejsou doprovázeny dalšími blízkými či velmi podobnými druhy v okolí. Vzhledem k tomu, že oba jsou zařazeny mezi kriticky ohrožené taxony a jsou pod ochranou evropského projektu Natura 2000, zaslouží si naši prvořadou pozornost. and Both taxa (Cerastium alsinifolium and Minuartia Smejkalii) with similar evolutionary history have for years been included among the endemic species of the Czech serpentine substrate, not accompanied by other near or similar species in given localities and their neighbourhood. Both species are critically endangered and protected under the European Natura 2000 project and therefore deserve special attention.
The agamosporous and taxonomically critical Dryopteris affinis group was investigated as part of a cytogeographic and morphometric study of ferns in Central Europe. Material from 27 localities in the Czech Republic, Slovakia, Poland and Austria was sampled and evaluated using both morphometric multivariate and karyological analyses. Chromosome counts and flow cytometric analyses revealed the existence of two distinct triploid taxa (2n = 123) of differing genome size, which correspond to D. borreri and D. cambrensis, and of a rare pentaploid hybrid (2n = 205) D. ×critica (D. borreri × D. filix-mas). Morphometric analyses confirmed a clear separation between both triploid taxa. New quantitative characters were selected based on a discriminant analyses, and a key for the identification of the species is presented.
Water-lilies (the genus Nymphaea) are one of the most ancient groups of aquatic plants. Two species (N. alba and N. candida) are native to the flora of the Czech Republic, both are critically endangered. Morphological similarities, large phenotypic variation and putative interspecific hybridization pose difficulties for species identification. The amount of nuclear DNA was found to be a reliable characteristic that allows not only species but also their hybrids to be re - cognized. Native species are mainly threa - tened by the loss of suitable habitats and planting of garden cultivars in natural sites. and Klára Kabátová, Petr Vít, Jan Suda.
Druhy rodu Diphasiastrum (Lycopodiaceae) představují velmi problematickou skupinu evropské flóry. Příčinou komplikované taxonomie je zejména hybridizace (včetně introgrese). Článek popisuje morfologii, biosystematické charakteristiky, ekologii, příčiny ohrožení a následnou ochranu. Sekundární stanoviště jsou často vhodná pro většinu taxonů v centrální Evropě. Proto by měly být takové biotopy středem zájmu institucí zabývajících se ochranou přírody. and Species of the genus Diphasiastrum (Lycopodiaceae) represent a very problematic group of European flora. Their taxonomy is complicated by hybridization (incl. introgression) in particular. Morphology, bio-systematic characteristics, ecology, causes of endangerment and subsequent protection are phenomena described in this article. Secondary habitats are frequently favourable for most of the taxa in Central Europe. For this reason nature conservation institutions should focus on such biotopes.
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.
Two new apomictic triploid (2n = 3x = 51) species from the Sorbus latifolia group, S. portae-bohemicae M. Lepší, P. Lepší, P. Vít et K. Boublík and S. albensis M. Lepší, K. Boublík, P. Lepší et P. Vít, putative hybridogenous species originated from a cross between S. danubialis and S. torminalis, are distinguished and described based on a taxonomic and chorological revision of Sorbus bohemica (a hybridogenous triploid species from the same parental combination). A number of contemporary biosystematic techniques, including molecular (nuclear microsatellite markers), karyological (chromosome counts, DAPI flow cytometry) and multivariate and geometric morphometrics were used to assess the variation of the species and justify their independent taxonomic status. All three species occur sympatrically in the České středohoří Mts (NW Bohemia). Sorbus bohemica is recorded from 31 localities, based on a revision of herbarium vouchers and field research. Recent field studies failed to verify five of these localities. Sorbus portae-bohemicae is a stenoendemic in the Porta bohemica gorge (situated ca 7 km WNW of Litoměřice) where it grows in open oak forests (Luzulo-Quercetum and transition vegetation type to Melampyro nemorosi-Carpinetum) on ENE-facing slopes and rocks. The only known population of S. portae-bohemicae consists of 14 adult individuals. Sorbus albensis occurs at 12 localities W to NW of Litoměřice. The total number of individuals is estimated at 600. Most are in acidophilous oak forests (Luzulo-Quercetum and its mesic derivatives), scree forests (Aceri-Carpinetum) or shrubby slopes (Pruno-Ligustretum, Antherico-Coryletum). Populations of the new taxa show little genetic variation and are phenotypically homogenous and well separated from other Bohemian hybridogenous Sorbus species. A distribution map of the three species is provided. Photographs of the type specimens and in situ fructiferous individuals of the new species are presented.
Sorbus eximia Kovanda, a hybridogenous species that originated from the parental combination S. torminalis and S. aria s.l., is thought to be an apomictic species, which includes diploid and tetraploid individuals. The present study confirmed the existence of only triploid individuals. A new tentatively apomictic triploid (2n = 3x = 51) species from the S. latifolia group: S. barrandienica P. Vít, M. Lepší et P. Lepší is described based on a revision of S. eximia. This species is assumed to have originated from a cross between S. danubialis or S. aria s.l. and S. torminalis. A wide palette of biosystematic techniques, including molecular (nuclear microsatellite markers) and karyological analyses (chromosome counts, DAPI flow cytometry) as well as multivariate morphometric and elliptic Fourier analyses, were used to assess the variation in this species and justify its independent taxonomic status. Allopatric occurrences of both species were recorded east of the town of Beroun in the Český kras, central Bohemia (Bohemian Karst). A distribution map of the two species is provided. Sorbus eximia occurs at four localities (the total number of adults and juveniles is 100 and 200, respectively) in basiphilous thermophilous oak forests (Quercion pubescenti-petraeae), mesic oak forests (Melampyro nemorosi-Carpinetum), woody margins of dry grasslands (Festucion valesiacae) and pine plantations. Sorbus barrandienica has so far been recorded at 10 localities (ca 50 adults). Recent field studies failed to verify two of these localities. It is mainly found growing on the summits of hills, usually in thermophilous open forests (Primulo veris-Carpinetum, Melampyro nemorosi-Carpinetum, Quercion pubescenti-petraeae) and woody margins of dry grassland. Its populations exhibit minimal genetic variation and are phenotypically homogeneous and well separated from other Bohemian hybridogenous Sorbus species. The epitype of S. eximia is designated here, and a photograph of the specimen is included. Photographs of the type specimens and in situ individuals, and line drawings of both species are presented.
Over the last decade there has been a tremendous increase in the use of flow cytometry (FCM) in studies on the biosystematics, ecology and population biology of vascular plants. Most studies, however, address questions related to differences in genome copy number, while the value of FCM for studying homoploid plant groups has long been underestimated. This review summarizes recent advances in taxonomic and ecological research on homoploid plants that were made using FCM. A fairly constant amount of nuclear DNA within each evolutionary entity together with the often large differences between species means that genome size is a useful character for taxonomic decision-making. Regardless of the number of chromosomes, genome size can be used to delimit taxa at various taxonomic levels, resolve complex low-level taxonomies, assess the frequency of interspecific hybridization or infer evolutionary relationships in homoploid plant groups. In plant ecology and evolutionary biology, variation in genome size has been used for prediction purposes because genome size is associated with several phenotypic, physiological and/or ecological characteristics. It is likely that in the future the use ofFCM in studies on taxonomy, ecology and population biology of homoploid plants will increase both in scope and frequency. Flow cytometry alone, but especially in combination with other molecular and phenotypic approaches, promises advances in our understanding of the functional significance of variation in genome size in homoploid plants.