Caloplaca subpallida ( Teloschistaceae ) , a lichen species new to Poland : distribution , ecology and taxonomic affinities

Caloplaca subpallida, described from Europe by Magnusson [1], belongs to the C. ferruginea group [2,3], which includes species with whitish, greyish or blackish thalli lacking anthraquinones, and ferrugineous apothecia, which contain anthraquinones. The species of the group are characterized by their content of chemosyndromes based on 7-chloroemodin [4]. This is a large group of ca. 35 species [2,3], which have different habitat preferences, growing on siliceous or calcareous rocks, bark of trees, wood or bryophytes. According to Gaya et al. [5], the C. ferruginea group is polyphyletic and taxonomically very problematic; therefore the group is in urgent need of a thorough revision worldwide. However, some recent contributions to its understanding have been undertaken by Vondrák & Hrouzek [6], Arup et al. [7] and Arup & Åkelius [8]. The C. ferruginea group, represented by ca. 22 species in Poland [9–13], has not been subjected to detailed studies, although taxonomic notes on some species are included in the papers by Wilk & Flakus [10], Wilk & Śliwa [11] and Wilk [12], which refer to the following taxa: C. albolutescens (Nyl.) H. Olivier, C. conciliascens (Nyl.) Zahlbr., C. percrocata (Arnold) J. Steiner, C. soralifera Vondrák & Hrouzek and C. teicholyta (Ach.) J. Steiner. Furthermore, the two first authors of the present study have paid special attention on this species group during lichenological studies in SW Poland. Based on these surveys, Kossowska [13] reported C. cf. atroflava (Turner) Mong. from serpentinites of the Sudety Mts and the Przedgórze Sudeckie foreland; more recent work has shown that C. subpallida was included in the material published by Kossowska [13], and subsequent studies carried out in the same area by the first author yielded additional records of the latter species. In this paper, C. subpallida is reported as new to Poland, and a detailed description of the species with notes on its habitat and distribution are provided. Taxonomic affinities of the species with other taxa are discussed, with particular reference to C. oxfordensis based on the type material examination.


Introduction
Caloplaca subpallida, described from Europe by Magnusson [1], belongs to the C. ferruginea group [2,3], which includes species with whitish, greyish or blackish thalli lacking anthraquinones, and ferrugineous apothecia, which contain anthraquinones.The species of the group are characterized by their content of chemosyndromes based on 7-chloroemodin [4].This is a large group of ca.35 species [2,3], which have different habitat preferences, growing on siliceous or calcareous rocks, bark of trees, wood or bryophytes.According to Gaya et al. [5], the C. ferruginea group is polyphyletic and taxonomically very problematic; therefore the group is in urgent need of a thorough revision worldwide.However, some recent contributions to its understanding have been undertaken by Vondrák & Hrouzek [6], Arup et al. [7] and Arup & Åkelius [8].
The C. ferruginea group, represented by ca.22 species in Poland [9][10][11][12][13], has not been subjected to detailed studies, although taxonomic notes on some species are included in the papers by Wilk & Flakus [10], Wilk & Śliwa [11] and Wilk [12], which refer to the following taxa: C. albolutescens (Nyl.)H. Olivier, C. conciliascens (Nyl.)Zahlbr., C. percrocata (Arnold) J. Steiner, C. soralifera Vondrák & Hrouzek and C. teicholyta (Ach.)J. Steiner.Furthermore, the two first authors of the present study have paid special attention on this species group during lichenological studies in SW Poland.Based on these surveys, Kossowska [13] reported C. cf.atroflava (Turner) Mong.from serpentinites of the Sudety Mts and the Przedgórze Sudeckie foreland; more recent work has shown that C. subpallida was included in the material published by Kossowska [13], and subsequent studies carried out in the same area by the first author yielded additional records of the latter species.
In this paper, C. subpallida is reported as new to Poland, and a detailed description of the species with notes on its habitat and distribution are provided.Taxonomic affinities of the species with other taxa are discussed, with particular reference to C. oxfordensis based on the type material examination.

Material and methods
The study is based on material collected from the Sudety Mts (including the Pogórze Zachodniosudeckie foothills and the Przedgórze Sudeckie foreland) in SW Poland.Voucher material is lodged in WRSL and the private herbarium of K. Szczepańska (Hb.Szczepańska).Reference material from KRAM, MICH and MIN was also investigated.
Morphological characters were examined on dry material using a dissecting microscope and anatomical characters were observed on hand-cut sections and squash preparations mounted in water.The structure of paraphyses was observed in 25% KOH (K).K and 65% nitric acid (N) were used for chemical reactions.
All known Polish localities of C. subpallida are concentrated in the SW of the country, within the Sudety Mts, including Przedgórze Sudeckie foreland and Pogórze Zachodniosudeckie foothills (Fig. 3), the nine collecting sites located in natural outcrops or abandoned quarries.

Discussion
Caloplaca subpallida is a taxonomically difficult European species, its position being discussed for decades (e.g.[18]).In the 1990s, it was regarded as a member of the C. sideritis group and synonymized with C. oxfordensis Fink [19], the taxon described from North America.Subsequently, the latter species was reported from several European countries, e.g.Austria [20], France [21], Greece [22] and Germany [23].However, according to Arup [24], recent molecular studies reveal that C. oxfordensis and C. subpallida are two distinct species.
The studied material of C. subpallida is homogeneous, and morphologically and anatomically identical to Vězda's Fig. 2 Abandoned serpentinite quarry at Świerczyna Mt. as a typical habitat of Caloplaca subpallida.
exsiccate specimen of C. subpallida determined by Magnusson.The species is characterized by its grey, rimose-areolate to subsquamulose thallus, and distinctly orange apothecia, usually without grey thalline margins.The apothecia are broadly sessile on the thallus, grouped and usually flexuose due to mutual compression.The spores are narrowly ellipsoid and its isthmus is moderately wide, 2.5-4.0 µm.It is worth noting that a comparison of C. subpallida with the type material of C. oxfordensis revealed that the anatomy of apothecia of both taxa is very similar, but the thallus development varies significantly, being thick and distinct in C. subpallida and extremely thin and almost invisible in C. oxfordensis.Although morphological evidence for separating the two species is not strong, their distinction is confirmed by molecular data [24].