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AbstractElatine triandraSchkuhr is the most variable and widespread species within the genus ElatineL.; it has been recorded in all continents, except Antarctica, but it is mainly located in Europe. The study is based on an extensive data set of European literature, herbaria and web data that covers the period 1828–2012. The range of the species in Europe is disjunctive, covering the southern and western parts of the Central European Plain and the southern part of the Fennoscandian Shield. At a smaller scale, the species can also be found along some river valleys. In Central Europe many localities, particularly isolated ones in the northern part of the range, are now only historical. From the data set we determined that E. triandramay be best observed between May and October. We found that species records show a near-significant shift since 1828. Depending on the environmental conditions, individuals of the taxon develop as one of two morphs: terrestrial or aquatic. The aquatic morph is characterized by stems, internodes, lamina and petiole that are twice as long as those of the terrestrial form. Elatine triandraseeds show consistent characteristics, both in terms of morphs and populations. Our studies show that the best diagnostic features, in addition to the construction of flowers, are the size, shape and surface structure of seeds. In Central Europe, E. triandraoccurs exclusively in communities classified as Isoëto-Nano-Juncetea.

WetVegEurope is a research project (http://www.sci.muni.cz/botany/vegsci/wetveg) whose goal is to provide a synthesized formalized classification of the aquatic and marsh vegetation across Europe at the level of phytosociological associations. In order to achieve the project objective, a WetVegEurope database has been created (GIVD ID: EU-00-020, http://www.givd.info/ID/EU-00-020), which currently contains 375,212 vegetation plots of aquatic, marsh and wet vegetation types from 33 European countries. The WetVegEurope database includes datasets from pre-existing national and thematic databases and also 10,616 plots previously not digitalized or even unpublished. This database offers an extensive source of data for future studies on aquatic and marsh plant species and vegetation types at the European scale.

Lindernia procumbensin Poland: the relationship between weather conditions and the occurrence of the speciesNew data regarding the occurrence of Lindernia procumbens(prostrate false pimpernel) are discussed and its current geographical range in Poland is given. A comparison of its past and present distribution in Poland indicates an advancement of the distribution limit northwards, which may be caused by climate changes, mostly, by an increased number of heat waves in the warm half-year. The relationship between the occurrence of the species and specific meteorological conditions, especially, unusually hot and dry summer periods, is analysed using long-term meteorological surveys.