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.
Koniklece (rod Pulsatilla) patří mezi nápadné, časně zjara kvetoucí rostliny otevřených stanovišť. V naší květeně se vyskytuje pět původních druhů, všechny jsou však vzácné a mizejí, a proto figurují mezi zvláště chráněnými rostlinami. Hlavní příčinu jejich ústupu lze spatřovat v sukcesních změnách na stanovištích (především zarůstání) v důsledku upuštění od tradičních forem obhospodařování. Na příhodných lokalitách, na nichž mohou růst pohromadě různé druhy konikleců, přistupuje další riziko a tím je mezidruhové křížení. Nebezpečí hybridizace spočívá zejména v jejím často obtížném odhalení, které se neobejde bez použití moderních botanických technik. Ty se ukázaly být velice užitečné i při studiu našeho nejčastěji udávaného hybridního taxonu – koniklece Hackelova. and The genus Pulsatilla (pasque flower) contains about 30 species distributed mainly in the mountains of the northern hemisphere. Several species can grow in sympatry and be involved in interspecific hybridization. High phenotypic variation of parental taxa, however, precludes unambiguous hybrid determination. Genome size was found to be a~reliable species-specific marker which can elucidate patterns and processes in mixed populations.
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.
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.