Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects.We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives. Geosphere-Biosphere Program (IGBP) and DIVERSITAS, the TRY database (TRY-not an acronym, rather a statement of sentiment; https ://www.try-db.org; Kattge et al., 2011) was proposed with the explicit assignment to improve the availability and accessibility of plant trait data for ecology and earth system sciences. The Max Planck Institute for Biogeochemistry (MPI-BGC) offered to host the database and the different groups joined forces for this community-driven program. Two factors were key to the success of TRY: the support and trust of leaders in the field of functional plant ecology submitting large databases and the long-term funding by the Max Planck Society, the MPI-BGC and the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, which has enabled the continuous development of the TRY database.

An account of the taxonomy of the genus Potamogeton L. with special reference to species description and delimitation is presented. A key to the species is given, based as far as possible on vegetative characters. Detailed descriptions are provided for a total of 69 species which are regarded as sufficiently well known. Special emphasis is laid both on a complete list of relevant characters as well as on the judgement of their respective diagnostic values. All important synonyms are listed allowing direct access to most of the relevant taxonomic and floristic Potamogeton literature. 50 confirmed hybrids are listed and assigned to their putative parent species. Questions with respect to the taxa listed are formulated in notes on each of the species. A more general view and questions on future Potamogeton research are summarized in the conclusions."It is to be regretted that we never arrive to the truth but through some mistake or another" (J. O. Hagstrrm 1916)

The Pladias (Plant Diversity Analysis and Synthesis) Database of the Czech Flora and Vegetation was developed by the Pladias project team in 2014-2018 and has been continuously updated since then. The flora section of the database contains critically revised information on the Czech vascular flora, including 13.6 million plant occurrence records, which are dynamically displayed in maps, and data on 120 plant characteristics (traits, environmental associations and other information), divided into the sections: (1) Habitus and growth type, (2) Leaf, (3) Flower, (4) Fruit, seed and dispersal, (5) Belowground organs and clonality, (6) Trophic mode, (7) Karyology, (8) Taxon origin, (9) Ecological indicator values, (10) Habitat and sociology, (11) Distribution and frequency, and (12) Threats and protection. The vegetation section of the database contains information on Czech vegetation types extracted from the monograph Vegetation of the Czech Republic. The data are supplemented by national botanical bibliographies, electronic versions of the standard national flora and vegetation monographs, a database of more than 19,000 pictures of plant taxa and vegetation types, and digital maps (shapefiles) with botanical information. The data from the database are available online on a public portal www.pladias.cz, which also provides download options for various datasets and online identification keys to the species and vegetation types of the Czech Republic. In this paper, we describe the general scope, structure and content of the database, and details of the data on plant characteristics. To illustrate the data and describe the main geographic patterns in selected plant characteristics, we provide maps of mean values of numerical characteristics or proportions of categories for categorical characteristics on the map of the country in a grid of 5 longitudinal × 3 latitudinal minutes (approximately 6.0 km × 5.5 km). We also summarize the main variation patterns in the functional traits in the Czech flora using the principal component analysis.

A taxonomic revision of the Asian species of Stuckenia, a segregate of Potamogeton, is presented. Six species are recognized and their morphological descriptions, nomenclature and typification of relevant names are given. Distributions of all species are described and lists of representative specimens and distribution maps provided. Lectotypes are designated for 24 names and nomenclatural types are listed for 22 additional names. The correct name for the species known as Potamogeton recurvatus is Stuckenia pamirica (Baagöe) Z. Kaplan, comb. nova. Morphological variation at different levels within the genus is described and compared with different concepts of its taxonomic interpretation. Instructions on examination of key characters are given, together with a key to species. Colour photographs illustrate the general appearance of species as well as many identification details. The pattern of variation and taxonomic validity of the Siberian morphotypes S. subretusa and S. austrosibirica are analyzed. The plasticity of diagnostic characters of P. juncifolius and of P. helveticus from the European Alps, the infraspecific classification of S. filiformis in North America, and the taxonomic status of S. punensis described from Peru are also discussed.

No abstract

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:

No abstract

Even though the triple hybrid is sterile, it possesses an efficient strategy for its existence and became locally successful even in the parental environment, perhaps as a result of heterosis. The population investigated is the only one known of this hybrid, P. x torssanderi, worldwide. Isozyme analysis indicated the colony to be genetically uniform. The plants studied represented a single clone that seems to have persisted at this site for a long time.