Three lichen species of Micarea ( Pilocarpaceae ) new to Belarus

Micarea elachista, M. micrococca and M. misella are reported for the first time from Belarus. Their phenotypic characters, distribution and ecological preferences are given.


Introduction
The genus Micarea was described by Fries [1] to accommodate a crustose species with a green granular thallus and convex immarginate apothecia named M. prasina Fr.Currently the genus comprises ca. 100 species [2,3] and is considered to be polyphyletic combining a large number of phenotypically variable species, as well as a heterogeneity of infrageneric characters [4,5].Further studies will probably provide stronger support for the delimitation of at least some distinct phylogenetic lineages obtained by Andersen and Ekman [5] and based on mtSSU sequences, will legitimate descriptions of several new genera.Some steps towards a new nomenclature of these species have recently started, with Harris [6] transferring Micarea erratica (Körb.)Hertel, Rambold & Pietschm.into the new genus Leimonis R.C. Harris, and Ekman and Svensson [7] introducing the genus Brianaria S. Ekman & M. Svensson for species of the former Micarea sylvicola group.
During a recent fieldwork in the Gomel region in southeastern Belarus, three Micarea species new to the country were discovered and details of these records are presented here.

Material and methods
The lichen biota of 14 study plots established in 2011-2013 in different types of Scots pine forests were investigated; these were selected to represent: Cladonia-type, Calluna vulgaris-type, Vaccinium vitis-idaea-type, Pleurozium schreberi-type, Pteridium aquilinumtype, Vaccinium myrtillus-type, Oxalis acetosella-type, Polytrichum commune-type and Ledum palustre-type stands.The size of each plot was limited by forest sub-blocks and occupied 2-12 ha.In each plot, 10 trees were randomly selected and all lichens were registered within them.Secondary chemistry of the sorediate crustose lichens was analyzed by thin-layer chromatography (TLC) in solvent C according to the methods of Orange et al. [18].
Coppins [19] showed M. elachista to be a predominantly lignicolous species in Europe colonizing decorticate trunks or large stumps of old trees, but Czarnota [10] has also reported it frequently on the bark of Pinus sylvestris in NE Poland.
NOTE.According to phylogenetic analysis, M. micrococca is a polyphyletic taxon.For almost 20 years prior to 2002, this group of taxa was included in M. prasina [23] despite their different chemistry [19].However, the chemistry appeared to be a sufficiently diagnostic character in further studies and today the presence of methoxymicareic acid is the main feature distinguishing the M. micrococca complex from other members of the M. prasina group.Visual identification of M. micrococca s.str. is possible when it is fertile, since its apothecia are white or cream while other representatives of the M. micrococca complex have at least some greyish apothecia due to a trace of Sedifolia-grey pigment which turns K± violet and C± violet.The darkest morphs containing methoxymicareic acid may also belong to the recently separated M. byssacea (Th.Fr.) Czarnota, Guzow-Krzemińska & Coppins which probably also occurs in Belarus since it is found in neighboring regions [11] (and Czarnota, unpublished data).
In Belarus, both M. micrococca s.str.and M. micrococca s.lat.represent two distinct lineages of the complex [11], but the description, habitat and list of collections below are only given for M. micrococca s.str.
HABITAT.The species was found exclusively on bark of P. sylvestris in three pine forest types, all of which were well-lit with a sufficient amount of moisture, ranging from the wet Polytrichum-type to the medium humid Pleurozium schreberi-type.
GENERAL DISTRIBUTION.It is difficult to evaluate the true world distribution of M. micrococca s.str.as representatives of the M. micrococca complex were critically revised only recently [11], but it has been reported so far from the Czech Republic, Estonia, Finland, Germany, Lithuania, Poland, Slovenia and Switzerland [11,24].However, this corticolous lichen-forming fungus inhabiting acidic bark appears to be frequent in Europe especially within large more or less managed coniferous woodlands.SPECIMENS EXAMINED.Belarus, Gomel region, Gomel district: Kalinino forest, 1. Thallus inconspicuous, partially on pine bark as a thin algal film, and partially on the thallus of M. denigrata.Pycnidia numerous, black, stalked, containing Sedifolia-grey pigment, K+ violet, C+ violet.Mesoconidia simple, cylindrical, 5.0-5.5 × 1.4-1.6(-1.9).Apothecia absent in Belarusian material.No substances detected by TLC.
HABITAT.The species was collected in young Vaccinium vitis-idaea-type pine forest growing on the edges of bark plates in bark fissures of Scots pine.Kotlov [25] noted that Micarea misella is exclusively lignicolous in Russia, and Coppins [26] noted that it is almost always lignicolous and rarely grows on the bark of old trees.
GENERAL DISTRIBUTION.Micarea misella is reported from Europe and North America, as well as from South America [2] and the Asian part of Russia [21].Amongst neighboring countries, it occurs in Lithuania [20], Ukraine [27] and in adjacent regions of Russia [21], and in Poland [10] it is one of the commonest representatives of the genus.