Volumen 41 (2016): Heft 1 (March 2016)

The genus Aneura is represented in Poland by two species - A. pinguis and A. maxima. A. pinguis in contrast to A. maxima is a complex of cryptic species temporarily named A. pinguis species: A, B, C, and E. All species of the A. pinguis complex and A. maxima differ in their geographic distribution and habitat preferences. A. pinguis species A grows mainly on humus over limestone rocks in the Western Carpathians, A. pinguis species B occurs mainly on clay soil in Bieszczady Mts. and in clayish areas of lowlands, A. pinguis species C grows both in lowlands and mountains and it occupies mostly wet sandy soils, on the shores of oligotrophic lakes and river and mountain stream banks, A. pinguis species E is connected with calcareous rocks in flowing water in mountains. A. maxima grows over the country - both in lowlands and mountains, in marshes situated on the river banks.

To investigate present and historical distribution of Equisetum ×moorei in Poland and its habitat requirements, field studies at sites of potential occurrence of this hybrid taxon as well as literature and herbarium search were performed. As a results of these investigations, E. ×moorei was found at five contemporary and at a few historical localities in the present territory of Poland. Since the Equisetum populations near Olkusz (S Poland) showed phenotype similar, to some extent, to triploid hybrid E. ×ascendens, we performed nuclear DNA content analysis of these populations. However, it turned out that the investigated individuals belonged to a diploid taxon that can be ascribed to E. ×moorei.

The aim of this work was to investigate the diversity of diatom assemblages developed in the Przyrwa stream, to assess water quality based on benthic diatoms and to make an attempt at the identification of physicochemical factors having the greatest impact on the differentiation of diatom assemblages. Studies were conducted in 2011-2012 on the Przyrwa stream, a left-side tributary of the Wisłok River flowing through the city of Rzeszów and with its spring section located on the borders of the city. A total of 259 diatom taxa were identified in the Przyrwa stream during three studied seasons. At all investigated sites, the most abundant population consisted of Ulnaria ulna (Nitzsch) Compère, Cocconeis pediculus Ehrenb., Achnanthidium minutissimum (Kütz.) Czarnecki var. minutissimum, Navicula gregaria Donkin, Planothidium frequentissimum (Lange-Bert.) Lange-Bert., P. lanceolatum (Brébisson) Lange-Bert., Navicula lanceolata (C. Agardh) Ehrenb., Amphora pediculus (Kütz.) Grunow, Eolimna minima, (Grunow) Lange-Bert., Melosira varians C. Agardh and Cyclotella meneghiniana Kütz. Based on IPS (Specific Pollution Sensitivity Index) and GDI (Generic Diatom Index) indices, the ecological status of the Przyrwa stream was assessed as moderate to poor (mostly III-IV class of water quality), while the TDI (Trophic Diatom Index) index indicated a poor to bad ecological status (mainly IV-V class of water quality).

In Poland, the largest stretches of abandoned agricultural areas were formed at the end of the 1980s, along western and eastern borders, among others, in Przemyśl Foothills (Pogórze Przemyskie). Therefore, the research on the diversity of plant communities from abandoned agricultural areas as well as main directions and the rate of succession after the cessation of management was undertaken in the vicinity of twelve municipalities in south-eastern Poland. This research revealed that the dominating direction of changes of the abandoned agricultural area vegetation was vanishing of plant groups with segetal and meadow species and spreading of shrub communities. A general increase in the forestation rate of the researched abandoned agricultural areas from 10-40% of the area in 1970-1971 to about 30-70% in 2003-2004 may be the evidence of the occurrence intensity of those phenomena.

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.

A new locality of Pulsatilla patens (L.) Mill. in the Wyszków-Jegiel Forest District, in the southern part of Puszcza Biała (ATPOL EC79) is described. This locality is situated on an escarpment, at the edge of Peucedano-Pinetum fresh pine forest with elements of Serratulo-Pinetum mixed pine forest and Potentillo albae-Quercetum steppe oak forest. Good light conditions prevail in the place of plant occurrence. Studies carried out in 2008-2015 showed an increasing trend of P. patens population, though, recently, this population seems to be stable. The number of species accompanying the pasque-flower also increased in this time period. It was found based on the analysis of flora directly neighbouring the clumps of the pasque-flower. During 7 years, the number of taxa increased by 31.5% on plot I and by 25% on plot II. In the years 2011-2013, the pasque-flower was represented both by flowering (1-2) and vegetative individuals. Afterwards, the plant was present only in vegetative stage. The number of its leaves varied in time. The highest number of leaves - 14 per individual - was noted in 2014, and the lowest number (1) - in 2012. The reason for a decline in the number of plant clumps in the site Dalekie and, at the same time, the greatest threat was the excavation of sand from the escarpment. In 2012, this escarpment slid down and several clumps of the pasque-flower were destroyed. Forest management and digging up by wild boars were additional factors limiting the population. To preserve the site of P. patens, measures of active protection should be applied.