Contribution to the knowledge of some poorly known lichens in Poland IV. Bacidia fuscoviridis and Bacidina brandii

Bacidia fuscoviridis and Bacidina brandii, two lichen-forming fungi, are reported from Poland. Bacidia fuscoviridis, previously known from only one locality in Poland, has been found in several ranges of Western Carpathians on natural rocks as well as on hydrotechnic constructions. The only published collection of Bacidina brandii from Poland was re-examined, and determined as Bacidina sulphurella. In addition to the author’s recent collections, which are new to the Carpathians, B. brandii has been discovered several times in some Polish herbaria in materials labelled as Bacidina phacodes. Illustrated descriptions and taxonomic, ecological, and distributional notes are provided for both species.


Introduction
The study reported here is the fourth in a series of articles that describe records of poorly known and new lichenized fungi in Poland [1][2][3]. This paper presents the known distribution and original illustrated descriptions of two species, Bacidia fuscoviridis (Anzi) Lettau and Bacidina brandii (Coppins &  Wirth. Both species were already reported from Poland. Bacidia fuscoviridis was found only once in the Gorce Mts [4,5] and Bacidina brandii was published erroneously [6], being in fact a rare morph of Bacidina sulphurella (Samp.) M. Hauck & V. Wirth. In the meantime, true material of B. brandii has been found in some Polish herbaria and new records of both species have been made in the Polish Western Carpathians.

Material and methods
Bacidina brandii was for the first time discovered in an old collection of J. Nowak deposited in the herbarium of the Polish Academy of Sciences in Cracow (KRAM) mixed with other species labeled as Bacidina phacodes (Körb.) Vězda. Therefore all Nowak's specimens deposited in KRAM under the name B. phacodes were re-examined. As a result, other specimens of B. brandii were found. This was an inspiration for the search of its potential habitats in Western Carpathians. At the same time, two other collections from the Gorce Mts, deposited in the herbarium of the Gorce National Park (GPN), were investigated. Since B. brandii had already been reported from NE Poland [6], related material from the herbarium of the University of Warmia and Mazury in Olsztyn (OTLC) was also re-examined. Material from the private herbarium of P. v.d. Boom has been used as a reference.

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Bacidia fuscoviridis was mainly collected in 2008 during studies of lichens growing on hydrotechnic constructions in the Western Beskidy Mts; related specimens are stored in the herbarium of Gorce National Park (GPN).
For determination of studied species standard light microscopes and chemical reagents were used. Hand-made apothecial sections were mounted in water and K+ color reaction of pigmented tissues was checked. Internal characters of apothecia were determined in water.

Bacidia fuscoviridis (Anzi) Lettau
Distribution and ecology. This saxicolous species is well known from natural limestone areas in Europe, being found, for example, in the fluvial mesic zone of limestone riverbeds in Great Britain [10], on shaded limestone rocks in Bohemian Karst (Czech Republic) [11,12], and several limestone ranges of the Carpathians such as Muranska planina (Slovakia) [13] and Bükk Mts (Hungary) [14]. Other records are known, for example, from Ireland [15], Sweden [16], Estonia [17], Belgium, Luxembourg, France (including the Pyrenees) [18,19], several mountainous German states [7], Southern Bohemia [20,21], Switzerland [22], Austria [23], Italy [24], Romania [25], and Bulgaria (Vondrák, personal communication, 2014). In these localities, B. fuscoviridis was found on calcareous substrata, as well as sandstones and concrete, similarly to those mentioned below for Polish localities. Distribution and ecology. The known distribution of B. brandii might suggest that this species has some Atlantic preference, since it was found in the western part of Europe, namely Great Britain [27], Belgium [18], France and the Netherlands [28], in German states: Upper Lusatia [29] and Schleswig-Holstein [30]; however, the latter finding is uncertain, since a description of that specimen significantly differs from that mentioned in the protologue [28]. Additionally, B. brandii was also found in Iberian Peninsula [31], and to the east, in Lithuania [28,32].

Discussion
Based on apothecial characters of Bacidia fuscoviridis, especially strongly developed plectenchymatous excipulum composed of stout, radiating hyphae bound in a gelmatrix, the ontogeny of apothecia which are finally strongly convex and immarginate and the fusiform ascospores, this species is phenotypically more closely related to representatives of the genus Bilimbia de Not. [e.g., B. sabuletorum (Schreb.) Arnold]. Indeed, a recent phylogenetic study of the genus Lecania A. Massal., which included also some members of Bilimbia and Bacidia, showed the close affinity of B. fuscoviridis to Bilimbia s. str. [33]. Despite this, it is still kept within the genus Bacidia and regarded as a "hard-placed" taxon (e.g., [15,33]). Bacidia fuscoviridis is usually found in a sterile stage as more or less separated grey-green sorediate patches and probably for this reason is poorly recognized in the field or under-collected. In early stages of development, when young soralia are often punctiform, it can be confused with the thallus of Porpidia soredizodes (Lamy ex Nyl.) J.R. Laundon. The species, however, colonizes rather siliceous, acid rocks and differs by its chemistry, i.e., the presence of stictic acid, reacting P+ ginger [34]; Bacidia fuscoviridis has no secondary metabolites and grows on more or less calcareous rocks. Larger, more sorediate sterile patches of B. fuscoviridis superficially resemble Lecidella scabra (Taylor) Hertel & Leuckert, also found on calcareous substrata (including concrete), but the latter species differs chemically since it produces atranorin and several xanthones, reacting C+ orange [15].
Bacidia fuscoviridis is probably more frequent throughout Europe, but overlooked when sterile. Many records of this species relate to at least periodically wet and shaded localities within the forests or to surroundings of riverbeds, or to old, calcareous manmade walls. Occurrence of B. fuscoviridis on weirs, dams and other hydrotechnic constructions has not been emphasized to date.
Bacidina brandii was already reported from Poland by Kubiak and Sparrius [6], but erroneously, based on specimen OLTC-L-2109 which actually represents a morphotype of B. sulphurella (Samp.) M. Hauck & V. Wirth with a dull grey margin, which is also known from other sites (Czarnota, unpublished data). A similar collection from Prague (Czarnota 5967, GPN) was recently sequenced by Czarnota and Guzow-Krzemińska [35] showing it is really placed within linage of B. sulphurella.
At first glance flesh-colored apothecia of B. brandii resemble larger apothecia of B. chloroticula (Nyl.) Vězda & Poelt, B. delicata (Larbal. ex Leight.) V. Wirth & Vězda or B. phacodes (Körb.) Vězda having only slightly darker disc with a pale brownish tinge. Young ascocarps of B. brandii are flat and distinctly sessile with a paler, well-developed rim; later they are usually slightly convex with the margin more or less excluded. In water the apothecia become almost completely translucent (as for example in Dimerella pineti or B. phacodes) but inside, unlike the three above-mentioned members of Bacidina, they are more or less brown due to the Arnoldiana-brown pigmented (K+ dulling) hypothecium (distinctly visible also in apothecial sections). The excipulum, composed of radiating, stout hyphae with large lumina of outer cells up to 5-8(-10) µm diam., is another diagnostic character for this species.
Recently one specimen resembling a pale form of B. brandii in almost all characters was collected in the Beskid Niski Mts (Polish Carpathians) [Magurski National Park, W slope of Suchania hill, 49°30'29.6" N, 21°32'40.2" E, alt. ca. 430 m, on decaying wood of beech in the Carpathian beech forest, September 2009, leg. L. Betleja & R. Kościelniak (KRAP)]. Considering its minutely granular thallus composed of goniocysts and different excipular hyphae, perhaps it represents some undescribed taxon but this assumption requires further investigation.
Discovering B. brandii at higher elevations of Western Carpathians in southern Poland came as a surprise since previously it was regarded as an Atlantic species (see distribution and related literature above). In the Carpathians, this species inhabits hard wood of horizontal cut surfaces of tree stumps. Such a substrate was already mentioned by Diederich et al. [18], but elsewhere B. brandii was usually known to be terricolous on soil or plant debris [18,28], lignicolous on rotting stumps [28], and sometimes corticolous on roots and tree bases [15]. Recently, it has also been found on stems of Vaccinium myrtillus [32]. All these reports show that B. brandii has a larger ecological plasticity and is probably more widespread in Central Europe than we thought.