Some new records of Rhizocarpon from North-Eastern Poland and North-Western Belarus

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


INTRODUCTION
Rhizocarpon Ramond ex DC. is a large genus of ca 200 species belonging to the family Rhizocarpaceae.It is widely distributed throughout the world, especially in alpine and polar regions.Species of the genus grow on rock and are long living.They have been widely used in studies on moraine dating in a procedure known as lichenometry.
The species of Rhizocarpon predominantly colonise siliceous rocks, although some species occur on basic substrates; a number of taxa are parasitic on other lichens (Poelt, Hafellner 1982;Poelt, Vězda 1984;Holtan-Hartwig, Timdal 1987;Poelt 1990).Thomson (1967) divided the genus Rhizocarpon into taxa with a yellow thallus containing rhizocarpic acid (subgenus Rhizocarpon) and taxa with white, ashy or brown thalli lacking rhizocarpic acid (subgenus Phaeothallus).A comprehensive taxonomic study of yellow species of Rhizocarpon in Europe was conducted by Runemark (1956a, b), but intra-specific variation of the R. geographicum complex is still unclear (Wirth 1995).A comprehensive revision of the so-called R. obscuratum complex with taxa containing hyaline and muriform ascospores was carried by Fryday (2000a) and of the so-called R. hochstetteri complex with taxa containing hyline and one-septate ascospores was carried out by Fryday (2002).In the Nordic countries, the taxonomy of the non-yellow species of Rhizocarpon with hyaline and muriform ascospores is recognized by Ihlen (2004).

STUDY AREA
The study area comprises north-eastern Poland (the area acc. to Cieśliński 2003) and north-western Belarus.NE Poland consists of two administrative areas, Podlaskie and Warmińsko-Mazurskie voivodeships.NW Belarus consists of one administrative centre, Grodno.
Species of Rhizocarpon grow on erratics and stones in the area investigated.Those are postglacial boulders brought to the area by the Scandinavian ice-sheet in the Pleistocene.They occur individually or in larger clusters, forming boulder concentrations.Granite rocks constitute approximately 80% of erratic boulders in NE Poland and NW Belarus, the remaining ones being gneiss rocks.The greatest boulder concentrations in NE Poland can be found in the Suwalski Landscape Park with the greatest concentration of boulders in the lowlands in the "Głazowisko Bachanowo" reserve comprising ca ten thousand boulders (Kukwa, Fałtynowicz 2002).Fortifications dating from World War I in NW Belarus in the vicinity of Grodno are currently being investigated not only by historians but also by biologists.

MATERIAL AND METHODS
The material was collected during visits to respective habitats in north-eastern Poland (2002-2009) and north-western Belarus (1983-2008).Additionally, collections of Rhizocarpon deposited in the herbarium of the Institute of Biology, University of Białystok and GRSU, MSK-L herbaria were verified.Data concerning species of Rhizocarpon and their distribution in NE Poland was supplemented with literature data.
Species were verified and named according to Thomson (1997), Fryday (2002) and Ihlen (2004).Based on descriptions and recent taxonomic innovations as well as chemical, microscopic and morphological characters, an original key to all Rhizocarpon species found in the study area was prepared and is presented here.Chemical analyses were performed using thin-layer chromatography (TLC) according to Orange et al. (2001) with the use of solvents A and C. Th. Fr., Lichenogr. Scand. 1: 625 (1874).
For the description of the species see Ihlen (2004).Spot test reactions: thallus K+ yellow, C−, KC−, PD−; medulla I+ blue, PD-, K-, C−.Substances detected by TLC: stictic acid in thallus and apothecia.The species was found on acid rocks.The habitats recorded were usually open and sunny.
R. eupetraeum is known from three localities in North-Eastern Poland (Cieśliński 2003).
For the description of the species see Poelt (1988).Spot test reactions: medulla I+ blue, K-, C-, PD-; UV+ bright orange.Substances detected by TLC: rhizocarpic acid, psoromic acid in thallus and apothecia.The species was observed on acidic rocks, on boulders.
For the description of the species see Thomson (1997).Spot test reactions: me-or the description of the species see Thomson (1997).Spot test reactions: medulla I+ blue, C+ red, PD-, K-.Substances detected by TLC: gyrophoric acid, stictic acid and norstictic acid in thallus and apothecia.The species was found on acidic rocks.
note.It is the first record of the species from North-Western Belarus.
For the description of the species see Fryday (2002).Spot test reactions: thallus K−, C−, PD−; medulla K−, C−, PD−, I−.Substances detected by TLC: lichen products not detected.The species was found on acidic rocks.
note.It is the first record of the species from Belarus.
For the description of the species see Ihlen (2004).Spot test reactions: thallus K-; medulla I-.Substances detected by TLC: lichen products not detected.The species was found on acidic rocks.
note.This is the first records of the species from Belarus.Anders, Hedwigia 64: 261 (1923).
For the description of the species see Ihlen (2004).Spot test reactions: thallus K+ yellow; medulla I-, K-, C-, PD-.Substances detected by TLC: stictic acid in thallus and apothecia.The species was found on acidic rocks.
note.This is the first record of the species from North-Western Belarus.
For the description of the species see Thomson (1997).Spot test reactions: thallus K+ yellow, C-; medula I+ blue, K-, C-, PD-.Substances detected by TLC: stictic acid in thallus and apothecia.This species was found on acidic rocks, on boulders.
For the description of the species see Fryday (2000b).Spot test reactions: thallus K+ yellow, C−; medulla I−, C−, K+ red, PD+ orange.Substances detected by TLC: stictic acid in thallus and apothecia.The species was found on acidic rocks, on boulders.
Poland (Cieśliński 2003) and six species in Belarus (Gorbach 1973).Of the eight taxa presented here, seven species of Rhizocarpon are reported for the first time for north-western Belarus, including three for Belarus.The occurrence of three species reported from NE Poland in literature data was confirmed in this study, with new localities recorded for them.
Rhizocarpon distinctum is the only common species in the study area while others are rare or very rare and were found at single localities.
Rocks and boulders, occurring singly or in small groups, are mostly suitable for their development in the lowland.In NE Poland, the area of the Suwalski Landscape Park covers lowland regions with a particularly large accumulation of mostly granite and gneiss boulders (Kukwa, Fałtynowicz 2002;Zalewska et al. 2004b).Boulders, stones and pebbles are in different habitat types: in the fields, balks, pastures, roads, on the slopes, in forests and their edges.Among the Rhizocarpon species characterized in the paper, R. geographicum and R. lecanorinum are rare in the lowlands.In NW Belarus, rare species of Rhizocarpon were recorded on the fortifications from World War I in Grodno.