2018): Distributions of vascular plants in the Czech Republic. Part 7. -Preslia 90: 425-531.The seventh part of the series on the distributions of vascular plants in the Czech Republic includes grid maps of 104 taxa in the genera Anthriscus, These maps were produced by taxonomic experts based on examined herbarium specimens, literature and field records. Many of the studied native species are on the national Red List. The genus most affected by decline in abundance is Gentianella, which includes six taxa extirpated from this country and six taxa critically threatened. Another group with a high proportion of endangered species comprises aquatic and wetland plants, which are represented by Callitriche hermaphroditica, Hydrocharis morsusranae, Najas minor, Pseudognaphalium luteoalbum and Stratiotes aloides. Other ecologically specialized groups include mainly montane wetland plants (Epilobium anagallidifolium, E. nutans and Rubus chamaemorus) and plants of rocky habitats (Polypodium interjectum, Trichomanes speciosum and Woodsia ilvensis). The previously rare Woodsia alpina has been extirpated from this country. Alien species mapped in this paper include both archaeophytes and neophytes, mainly from the genera Anthriscus, Cochlearia, Elodea, Epilobium, Hordeum and Phleum. Cochlearia danica, Dittrichia graveolens and Limonium gmelinii have recently colonized habitats along the roads treated by de-icing salt. Senecio inaequidens has also spread mainly along motorways. Epilobium adenocaulon is another successful neophyte; it is now widespread throughout this country and the most successful hybrid parent within the genus. Neophyte aquatics are represented by Egeria densa, Elodea canadensis and E. nuttallii. Spatial distributions and often also temporal dynamics of individual taxa are shown in maps and documented by records included in the Pladias database and available in electronic appendices. The maps are accompanied by comments that include additional information on the distribution, habitats, taxonomy and biology of the taxa. K e y w o r d s:

This study documents the mixed reproductive mode of a hybrid between apomictic and sexual ferns. Both sexual reduced and apomictic unreduced spores can be produced by a single individual, and even within a single sporangium. Both types of spores give rise to viable F2 generation gametophytes and sporophytes.

and 4 Institute of Botany, Academy of Sciences of the Czech Republic, Pr ů honice 1, CZ-252 43 Pr ů honice, Czech Republic• Premise of the study : Genome duplication and interspecifi c hybridization are important evolutionary processes that significantly infl uence phenotypic variation, ecological behavior, and reproductive biology of land plants. These processes played a major role in the evolution of the Dryopteris carthusiana complex. This taxonomically intricate group composed of one diploid ( D. expansa ) and two allotetraploid ( D. carthusiana and D. dilatata ) species in Central Europe. Overall phenotypic similarity, great plasticity, and the incidence of interspecifi c hybrids have led to a continuous dispute concerning species circumscription and delimitation.• Methods : We used fl ow cytometry and multivariate morphometrics to assess the level of phenotypic variation and the frequency of hybridization in a representative set covering all recognized species and hybrids.• Key results : Flow cytometric measurements revealed unique genome sizes in all species and hybrids, allowing their easy and reliable identifi cation for subsequent morphometric analyses. Different species often formed mixed populations, providing the opportunity for interspecifi c hybridization. Different frequencies of particular hybrid combinations depended primarily on evolutionary relationships, reproductive biology, and co-occurrence of progenitors.• Conclusions : Our study shows that genome size is a powerful marker for taxonomic decisions about the D. carthusiana complex and that genome size data may help to resolve taxonomic complexities in this important component of the temperate fern fl ora.

Introgressive hybridization is an important evolutionary process frequently contributing to diversification and speciation of angiosperms. Its extent in other groups of land plants has only rarely been studied, however. We therefore examined the levels of introgression in the genus Diphasiastrum, a taxonomically challenging group of Lycopodiophytes, using flow cytometry and numerical and geometric morphometric analyses. Patterns of morphological and cytological variation were evaluated in an extensive dataset of 561 individuals from 57 populations of six taxa from Central Europe, the region with the largest known taxonomic complexity. In addition, genome size values of 63 individuals from Northern Europe were acquired for comparative purposes. Within Central European populations, we detected a continuous pattern in both morphological variation and genome size (strongly correlated together) suggesting extensive levels of interspecific gene flow within this region, including several large hybrid swarm populations. The secondary character of habitats of Central European hybrid swarm populations suggests that man-made landscape changes might have enhanced unnatural contact of species, resulting in extensive hybridization within this area. On the contrary, a distinct pattern of genome size variation among individuals from other parts of Europe indicates that pure populations prevail outside Central Europe. All in all, introgressive hybridization among Diphasiastrum species in Central Europe represents a unique case of extensive interspecific gene flow among spore producing vascular plants that cause serious complications of taxa delimitation.

Sex expression of homosporous ferns is controlled by multiple factors, one being the antheridiogen system. Antheridiogens are pheromones released by sexually mature female fern gametophytes, turning nearby asexual gametophytes precociously male. Nevertheless, not all species respond. It is still unknown how many fern species use antheridiogens, how the antheridiogen system evolved, and whether it is affected by polyploidy and/or apomixis. We tested the response of 68 fern species to antheridiogens in cultivation. These results were combined with a comprehensive review of literature to form the largest dataset of antheridiogen interactions to date. Analyzed species also were coded as apomictic or sexual and diploid or polyploid. Our final dataset contains a total of 498 interactions involving 208 species (c. 2% of all ferns). About 65% of studied species respond to antheridiogen. Multiple antheridiogen types were delimited and their evolution is discussed. Antheridiogen responsiveness was not significantly affected by apomixis or polyploidy. Antheridiogens are widely used by ferns to direct sex expression. The antheridiogen system likely evolved multiple times and provides homosporous ferns with the benefits often associated with heterospory, such as increased rates of outcrossing. Despite expectations, antheridiogens may be beneficial to polyploids and apomicts.