New localities of <em>Rhizocarpon distinctum, R. geographicum</em> and <em>R. reductum</em> are reported from NE Poland. <em>Rhizocarpon distinctum, R. grande, R. hochstetteri, R. lavatum, R. petraeum, R. polycarpum</em> and R. reductum</em> are reported from NW Belarus for the first time. <em>Rhizocarpon hochstetteri, R. lavatum</em> and <em>R. polycarpum</em> are new to Belarus. A key to species occurring in the area is given.

Monitoring of lichens as bioindicators of air pollution has been conducted in Sokółka. On the basis of the occurrence of indicator epiphytic and epilithic lichen species, the scale of lichen sensitivity for the city has been developed and lichen zones have been designated. The zone pattern was not of insular character, and as a result there was no “total lichen desert”. The distribution of lichen zones reflects the intensity of anthropogenic pressure within the town. The least favourable conditions for lichen growth have been recorded in the town centre, while the green areas have shown the most beneficial impact on the lichen test sites

A paper presents a list of 89 species found in Supraśl town (Podlasie, NE Poland). The investigations in the area of Supraśl were carried out in 2013-2014, on 41 research stands. Eighteen species are considered to be threatened in Poland. The lichens occur on all substrate types: soil, decaying wood, bark of all trees and shrubs species, boulders, concrete, foundation, mortar, plaster and bryophytes. Valuable components of the lichen biota belong mostly to the group of threatened species not only on the regional, but also on the national scale. There are: Anaptychia ciliaris, Pleurosticta acetabulum, Ramalina fastigiata and others.

In northeastern Poland, the chemical variation of the Cladonia chlorophaea-pyxidata group was much neglected, as TLC has not been used in delimitation of species differing in the chemistry. As a great part of herbal material of University in Bialystok from NE Poland was misidentified, I found my studies to be necessary. Based on the collection of 123 specimens deposited in Herbarium of University in Bialystok, nine species of the C. pyxidata-chlorophaea group are reported from NE Poland. The morphology, secondary chemistry, and ecology of examined lichens are presented and the list of localities is provided. The results revealed that C. fimbriata is the most common species in the northeastern Poland, comprising around 33% of the studied specimens. Cladonia conista, C. cryptochlorophaea, and C. merochlorophaea are known only from very few locations. This study shed light on the role of the lichens substances to diagnosis of the species of C. pyxidatachlorophaea group.

Based on collections of P. Czarnota deposited in the GPN herbarium, 8 species of <em>Rhizocarpon</em> are reported from the Gorce Mountains. Two of them, <em>R. lavatum</em> and <em>R. reductum</em> are reported from the Gorce Mts for the first time, instead of erroneously determined <em>R. obscuratum</em>. This species was previously misinterpreted due to taxonomic and nomenclatoric uncertainties.