The paper presents the results of geobotanical studies on the distribution and resources of Aster tripolium L. and Plantago maritima L, two rare halophytes in Poland. The research was conducted in northern Poland, along the Baltic coast in 2013. The present distribution of the two species was compared with historical data and general trends of and threats to these two species were examined. In total, 33 sites of A. tripolium and 18 of P. maritima were found in the research area. The resources of both species have been perceptibly depleting during last 150 years, which is mostly due to human agencies (e.g. habitat devastation caused by growing urban areas and the change in management and/or habitat condition). In order to preserve both species, it may be necessary to start an ex situ conservation program.
Gdańsk Pomerania is a region characterized by unique physiographic features and diverse flora. This region, as many other areas, is subject to numerous accelerating transformations. The occurrence of numerous species on their range edges and on isolated stands, e.g. mountain and xerothermic grassland species, was an important criterion in the development of a regional red list of vascular plants of Gdańsk Pomerania (). On this list, 648 species of vascular plants, which constitute about 39% of the regional flora and 26% of all Polish flora, are considered to be endangered at various levels. In total, 47 species have been declared extinct in the aforementioned region (RE), 39 taxa are considered as critically endangered (CR) and 109 – as endangered (EN). Further 222 plant species are classified as vulnerable (moderately endangered) (VU), 124 have low risk categories (NT or LC) and there are 107 taxa of unknown threat, due to lack of sufficient information (DD). The aim of this work was to synthesize endangered components of Gdańsk Pomerania vascular plant flora for their better recognition and characterization. Among the species varying in threat degrees, the authors identified species protected by law and endangered in Poland as well as globally. In addition, the participation of species diagnostic of individual phytosociological units was verified. Also, the share of taxa representing various geographical elements was indicated.