INTRODUCTION

The genus Xanthoria has, in similarity with several other well-known lichen genera, been heavily re-evaluated in the molecular era. Morphological characters used for delimitations of species and genera showed good correlation with molecular data. Seventeen lichen groups, earlier included in Xanthoria, have been segregated as separate genera (Kondratyuk et al. 2022 b). Of approximately 50 Xanthoria species in the pre-molecular era (Kärnefelt 1989), only 13 species remain in the genus in its strict sense (Kondratyuk et al. 2022 b), although many new species have been described both in Xanthoria s. str. and its segregates.

The present work is limited to Xanthoria in its strict sense, where several subclades can be discerned, one of which is the Xanthoria ectaneoides subclade. The basionym for Xanthoria ectaneoides (Nyl.) Zahlbr. is Physcia ectaneoides Nyl., described in the 19th century (Nylander 1883). The species is revised using a recent collection from areas around the southwestern part of the Baltic Sea. The phylogeny is based on ITS-sequences. Non-molecular characters were investigated for all specimens including the type specimen of X. ectaneoides from France. Xanthoria ectaneoides has been considered as a synonym of X. aureola (Ach.) Erichsen (Gaya et al. 2012, 2015, Lindblom and Ekman 2005). The wide species concept for Xanthoria parietina and X. aureola does not have support from molecular data.

Already in the 1990s, the senior author was aware of an undescribed taxon in Scandinavia with very long ascospores, to 20 µm long, and very wide ascospores septa, 11–12 µm wide. The undescribed taxon was recognised by its spore size since the ascospores of Xanthoria parietina are smaller, i.e. 10–15 × 6–8 µm with 6–8 µm wide septa. In 2022–2023 an extensive material of Xanthoria s. str. was collected in the southwestern Baltic Sea area, in connection with a project on lichenicolous fungi growing on Xanthoria (Kondratyuk et al. 2023). The undescribed taxon was found to be frequent in the investigated area.

Prior to describing a new species, a revision of all available types of old taxa of the genus Xanthoria was performed. Long ascospores (to 20 µm long) with wide septa (ca 11–12 µm) are revealed here as specific for Xanthoria ectaneoi des (Nyl.) Zahlbr. (Nylander 1883), the second species to be described in Xanthoria after X. parietina (Linnaeus 1753).

The aim of this paper was to revise the Xanthoria ectaneoides complex, based on material from the area around the southwestern part of the Baltic Sea, using morphology, anatomy and molecular phylogeny. This integrative approach in taxonomy of the genus Xanthoria, i.e. correlation between morphology and anatomy, particularly details of ascospores and their septa, was elaborated by the Austrian lichenologist Josef Poelt and his colleagues in the premolecular era (Giralt et al. 1993, Kondratyuk and Poelt 1997, Poelt and Petutschnig 1992 a, b, etc.). Several species described later were confirmed by molecular phylogeny (Arup et al. 2013, Kondratyuk et al. 2013, 2017, 2020).

MATERIAL AND METHODS

Lichen-forming fungi of the Xanthoria calcicola and the X. parietina complexes occurring on hard substrates, i.e., rocks, bricks, tiles and metal roofs were collected at 65 localities in southern Scandinavia, i.e. Skåne, the southernmost province of Sweden, southern Denmark and northern MecklenburgVorpommern and Schleswig-Holstein in Germany (Table 1). The specimens will preferably be deposited at C, GB, KW-L, LD, some of them will be distributed in the exsiccate Plantae Graecenses. The revision was mainly based on our own collections and type specimens of Xanthoria aureola, X. calcicola and X. ectaneoides.

The specimens were sprayed with water preferably from ten minutes to half an hour before they were removed from the substrate. Mature apothecia were cut by hand. Fifteen sections of each apothecium were mounted in the same water droplet to contain a sufficient amount of ascospores, at least 50 in light field of the microscope, for statistic measurements. As co spores were exclusively measured outside of asci and sections. At least 50 measurements of adult ascospores were performed and included in the further statistical analysis.

The specimens were studied and determined microscopically and vouchers for DNA-analyses prepared at the unit of Molecular Cell Biology, Department of Biology, Lund University.

RESULTS AND DISCUSSION

Molecular data on Xanthoria species

To check positions of the newly collected specimens, ITS-sequences from all Xanthoria species available in the GenBank were included in the analysis (Table 2). The number of Xanthoria sequences in the GenBank are submitted under the name Xanthoria parietina, in the pre-molecular era considered to be one of the most thoroughly studied of all lichen species (Honegger 1996), however, today it is clear that many of these sequences represent other species. Whole genomes of several Xanthoria aureola, X. mediterranea, X. steineri as well as Xanthoria sp. 1 and Xanthoria sp. 2 are now available (Tables 2 and 4) (Llewellyn et al. 2023). The nrITS sequences of these species mentioned, except for Xanthoria sp. 2 (data on nrITS of which are still not available via BLAST) were extracted from the whole genome and used in the present phylogeny analysis.

Table 4

Molecular data on members of the genus Xanthoria (data on vouchers ‘Xanthoria sp.’ available in GenBank are not included here)

	parietina	aureola	stei- neri	mediterranea	ectaneoides	cal- cicola	coomae	polessica	monofoliosa
nrITS	257	3		2	13	12	4	2	3
18S nrSSU	10	1			1	1
28S nrLSU	22	1				2
12S mtSSU	7	1		1	2	5	2		1
23S mtLSU	12				3	1
hydrophobin	57				12	3
beta-tubulin	30			1	5	1
RPB2	1	1				1
RPB1	1	1				1
polyketide synthase gene	2
28S-18S intergenic space	35	2				3
putative non- ribosomal peptide synthase-like gene	1
SLA2 gene, DNA lyase gene and MAT 1-2-1 gene	1
whole genome	1	1	1
Total	436	11	1	3	36	30	3	2	1

The phylogenetic tree based on ITS-sequences is divided in two main clades, the X. calcicola and X. parietina clades, and Xanthoria monofoliosa positioned on a separate branch (Arup et al. 2013, Fedorenko et al. 2009, 2012, Gaya et al. 2012, 2015, Kondratyuk et al. 2014, 2017, 2020).

The matrix of nrITS sequences contains more than 330 specimens of the genus Xanthoria, including also data on specimens named as Xanthoria sp. However, vouchers incorrectly named Xanthoria parietina are nested among other species, i.e. Xanthoria coomae, X. monofoliosa, X. polessica, and even true Xanthoria ectaneoides s. str. In the same way, sequences labelled X. calcicola and X. ectaneoides in the GenBank are also spread on several branches. Some separate subclades probably represent undescribed species.

To illustrate the tree in the best way, only a selection of the sequences available in the GenBank were included. Thus, for Xanthoria calcicola, X. coomae, X. monofoliosa and X. parietina, the most frequently represented species in the GenBank, only 5–7 sequences were selected, whereas all sequences for Xanthoria polessica, X. ibizaensis, X. mediterranea where included. Species names are set according to positions in the tree, whereas their names in the GenBank submissions, if different, are indicated within brackets references / footnotes (Fig. 1 tree, and Table 4).

View Full Size

Consensus MP tree after nrITS of the members of the genus Xanthoria. Abbreviations: * = data are submitted to GenBank under Xanthoria parietina, ** = data provided under Xanthoria sp., *** = data are provided under Xanthoria ectaneoides

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

An ITS-sequence extracted from the whole genome of Xanthoria steineri (Llewyllen et al. 2023) helps to confirm additional specimens of this species from Cyprus.

NEW MOLECULAR DATA

Sequences for some Xanthoria species are produced within this study for the first time. These are Xanthoria ibizaensis S. Y. Kondr et A. S. Kondratiuk, the holotype, described from the Balearic Islands (Kondratyuk et al. 2020), position in the Xanthoria monofoliosa subclade (Fig. 1), X. streineri I. M. Lamb, described from Iran, is confirmed from Cyprus in this study using a voucher by Scherrer and Honegger (2003) mentioned as Xanthoria sp. SH5-2001, X. ectaneoides, six vouchers, the new species X. pylyporlykii (described below), five vouchers, and Xanthoria aff. aureola, one voucher.

Xanthoria ectaneoides (Nyl.) Zahlbr.

(= Physcia ectaneoides Nyl.)

(Figs 2–4)

View Full Size

The type specimen of Xanthoria ectaneoides (Nyl.) Zahlbr. (lectotype, H-NYL 32723), with Nylander’s line drawings and handwritten measurements of ‘conidia’. These, however, were in fact ascospores

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

View Full Size

Xanthoria ectaneoides (Nyl.) Zahlbr. (photo in field condition, Lund 25.04.2023)

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

View Full Size

Xanthoria ectaneoides (Nyl.) Zahlbr. (SK23707, nrITS voucher LD-M52) host thallus heavily damaged by lichenicolous fungus Telogalla olivieri s. l.

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

France: ‘Monspelii, Lavalette’ [Herault, Montpellier], lectotype, H-NYL 32723.

Thallus from almost undeveloped or network-like with very narrow thalline main lobes where mostly apothecia make this lichen or ‘anularis’ type i.e. similar to the Euroasian species Kudratoviella anularis (Clauzade et Poelt) S. Y. Kondr., L. Lőkös, Kärnefelt et A. Thell). The central portion of the thallus is degenerate, thus only peripheral parts are present (Kondratyuk et al. 2022 a), to an almost single-level or more or less film-like, rosette-formed thallus, i.e. the X. coomae type of thallus, where separate lobes are not seen in the centre. Comparatively distinctly developed in the peripheral zone; small secondary sublobules present in the centre, often originating from remains of overmature apothecia as narrow overlapping parts.

Apothecia small, 1(–2) mm diam., numerous, usually widely dispersed, rarely crowded, in the centre of the thallus, lecanorine with more or less plane disc, usually with a smooth, rarely crenulate, thalline margin; ascospores narrow and rather long, 15–18(–20) × 5–7 µm with very wide ascospore septum 10–13 µm.

Xanthoria ectaneoides and X. pylyporlykii form sister branches in the Xanthoria ectaneoides subclade (Fig. 1). Xanthoria ectaneoides used to be recognised exclusively by its secondary sublobules. In this study, species delimiting characters of the ascospores are added. Its closest relative, Xanthoria pylyporlykii is lacking secondary sublobules and differ by shorter ascospores and narrower ascospore septa, the X. coomae type.

Ecology: This species was described from limestone. From our study it is rather common in the southwestern Baltic area on hard substrates: tiles, concrete, metal and granite, as well as rarely collected on bark of trees.

Distribution: Since this species was considered a synonym of X. aureola, data on ecology and distribution are incomplete during the latest decades and therefore not considered. Xanthoria ectaneoides is found at more than 30 localities in Sweden, Denmark and Germany (Fig. 9, Table 1), however, is probably widely distributed in the European continent.

View Full Size

The type specimen of Xanthoria aureola (Ach.) Erichsen (lectotype, H-NYL 32723)

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

View Full Size

Xanthoria aff. aureola 1 (voucher LD-M84) from Gørløse locality, Bornholm, Denmark

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

View Full Size

Xanthoria aff. aureola 1 (voucher LD-M84) from Gørløse locality, Bornholm, Denmark. Enlarged portion with apothecium (upper), and enlarged portion with isidia (lower)

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

View Full Size

Xanthoria pylyporlykii S. Y. Kondr., Kärnefelt et A. Thell (holotype)

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

View Full Size

Distribution of Xanthoria ectaneoides complex in the southwestern part of the Baltic Sea area: Xanthoria ectaneoides (upper), X. pylyporlykii (lower). Numbers of localities after Table 1

Citation: Acta Botanica Hungarica 66, 1-2; 10.1556/034.66.2024.1-2.3

• Download Figure
• Download figure as PowerPoint slide

Taxonomic notes: Xanthoria ectaneoides has a characteristic thallus with a smooth central part, numerous secondary sublobules, lecanorine apothecia usually distantly spread, emarginate or with subconvex disc as overmature, the ascospores are the longest observed in the genus and the septum is the widest in the genus.

Material referred to as ‘Xanthoria ectaneoides sensu German lichenologists’ was typically used for sterile thalli densely covered by secondary lobules. Although we believe that most of these thalli really was true X. ectaneoides, this species appears as richly fertile in this study, with a variable development of the thallus.

Nylander’s species Physcia ectaneoides (= Xanthoria ectaneoides (Nyl.) Zahlbr.) was accepted as a questionable taxon with numerous, very long and strap-shaped lobes, with a bulky appearance in the Mediterranean and Atlantic Europe, considered as a synonym of X. aureola (Gaya et al. 2012, 2015, Lindblom and Ekman 2005). This approach is not followed in this study since the two species are not the closest relatives but belong to different subclades.

The unfortunate confusion of measurements of conidia and apothecia in Nylander’s original description have caused incorrect conclusions. At any case, X. ectaneoides wears the longest ascospores and widest septa of the genus. It is often supplied with sublobulae in the centre, which are lacking in closely related X. coomae. Xanthoria ectaneoides was earlier recognised by a bulky thallus due to numerous strap-like, overlapping lobes and by X. parietina type ascospores (see also Xanthoria sp. 2). However, true X. ectaneoides has no strap-like lobules forming a bulky thallus, but much shorter and narrower lobes, named ‘secondary sublobules’, a term introduced here.

The systematic position of X. ectaneoides and the new species X. pylyporlykii constitute a sister branch to X. coomae (see Fig. 1).

The position of Xanthoria ectaneoides is confirmed by five specimens, which are morphologically and anatomically identical with Nylander’s type specimen of Physcia ectaneoides, however, the specimen is too old for a molecular study.

Most specimens determined as Xanthoria ectaneoides sensu German lichenologists based upon of numerous thalline sublobules on rocky surface, most likely belong to true Xanthoria ectaneoides. Richly fertile specimens of Xanthoria ectaneoides are common both in Scandinavia and Germany and can easily be confirmed by their nrITS-sequences (Table 1).

Specimens of Xanthoria ectaneoides examined: Nexø SK23703 (voucher LD-M61 for nrITS), SK23711 (voucher LD-M69 for nrITS), SK23707 (voucher LD-M52 for nrITS), SK23793, SK23795, SK23799, SK23800, SK23717, SK23719, SK23712, SK23793, SK23800. – Stehag SK23908, SK23890G, SK23890K, SK23905C, SK23901. SK23917B, SK23917, SK23971, SK23970, SK23968, SK23966, SK23964, SK23487, SK23488, SK23969, SK23963, SK23900. – Tårnby SK23932, SK23927D, SK23927C, SK23927B, SK23922E, SK23922C, SK23922B, SK23922, SK23917C, SK23917D, SK23917C, SK23939, SK23933F, SK23933E, SK23933D, SK23933C, SK23933B, SK23917, SK23930, SK23952. – Tårnby 918, 932, 931, 929, 928, 926, 924, 923, 922, 921, 920, 919, 933, 934, 945, 946, 947, 949, 950, 951, 954, 955, 956, 957, 958, 959, 962. – Marstal, concrete wall at sea coast, 27.05.2023 SK23847; Sandby / Fanefjord 524, 527; S Malmö 528; Norra Vrams 446, 447, 491; Nyker 450, 451; Everöd 555 (nrITS voucher LD-M70), 568; Igelösa 774; Skanör church 360. – Germany: Rostock SK23A12, SK23A11, SK23A09, SK23A01, SK23A04; Cammin, 1.10.2023 SK23A29; Russow SK23995, SK23994, SK23988, SK23987, SK23986, SK23985, SK23990; Alt Barlow SK23974, SK23975, SK23976, SK23978, SK23983, SK23977. – Farum SK23502 (nrITS voucher LD-M68), 506, 515, 572, 497, 535, 575, 571; Nyker 466, 467; S of Helsingborg 468, 469; SE Trelleborg 471, 484, 485; Igelösa 775; Tofta 779.

The Xanthoria coomae subclade is in need of an extended revision. Xanthoria coomae is commonly confused with the morphologically similar Xanthoria parie-tina (Fedorenko et al. 2009), whereas X. ectaneoides may include additional taxa.

Xanthoria sp. 2

The name Xanthoria ectaneoides was hitherto used along the coastal zone of Atlantic Europe for specimens with a narrow, strap-like, often semierect or semi-ascending lobes forming a rather bulky thallus, not considering the appearance of the ascospores. Such material is not conspecific with Xanthoria ectaneoides and therefore called ‘Xanthoria sp. 2’ in the phylogenetic tree (Fig. 1). This material, positioned in the Xanthoria calcicola subclade, will be revised in a future study since it cannot belong in Xanthoria ectaneoides s. str. (Fig. 1).

Xanthoria aureola (Ach.) Erichsen

Basionym: Parmelia aureola Ach. – Lichenogr. Univ.: 437 (1810).

Type: Sweden, ‘Suecia’ [Bohuslän province (= ‘Bahusia’), on seashore rocks] (H-ACH 1300 – lectotype, designated by Lindblom and Ekman 2005).

The description of Xanthoria aureola needs to be revised since it includes descriptions of both Xanthoria aureola s. str. (apothecia almost always absent, poorly developed ascospores, etc.) and Xanthoria sp. 2 (thalline lobes strap-shaped 0.3–1.3 mm wide, to slightly ascending, often irregularly overlapping in thallus centre, without vegetative diaspore, etc.).

The small, sterile and old type specimen of Xanthoria aureola is unusable for both spore- and DNA-studies (Fig. 5). It has rather wide and heavy thalline, closely attached to substrate, sometimes with lobe margins bent downwards, supplied with minute isidia, i.e. the type of isidia unique for the X. calcicola group. Thus, X. aureola, having minute isidia, is also morphologically different from both the non-isidiate and richly sublobulate true X. ectaneoides and the non-isidiate, strap-like lobulate species with a bulky thallus, here called Xanthoria sp. 2.

Molecular data for X. aureola were published by Lindblom and Gaya with colleagues (Gaya et al. 2012, 2015, Lindblom and Ekman 2005, Llewyllen et al. 2023). They also revealed the position in the Xanthoria calcicola subclade for X. aureola (Gaya et al. 2012, 2015, Lindblom and Ekman 2005). Lindblom and Ekman (2005) proposed to synonymise X. ectaneoides (Xanthoria sp. 2) with the Acharian species Xanthoria aureola. However, X. aureola is neither conspecific with Xanthoria sp. 2 nor, and even less, with X. ectaneoides s. str. (Fig. 1).

Furthermore, Xanthoria ectaneoides sequences in the GenBank from Sicily, Italy and Tunisia probably belong to Xanthoria mediterranea (but not to X. tendraensis) or close, maybe undescribed relatives to these two taxa (see Khodosovtsev et al. 2023).

Xanthoria aff. aureola 1

A first attempt to select fertile collections for DNA-vouchers of Xanthoria aureola was made in this study. The richly fertile specimen with minute isidia from Gørløse in Zealand, Denmark (voucher LD-M84) was included in our phylogenetic analysis as X. aff. aureola 1 (Fig. 1).

Xanthoria pylyporlykii S. Y. Kondr., Kärnefelt et A. Thell, spec. nova (Fig. 8)

MycoBank No.: 853037

Similar to Xanthoria ectaneoides, according to nrITS-sequences in sister position to X. ectaneoides, but differs in having wider thalline lobes, usually well-developed overlapping and irregularly orientated in the centre of the thallus, shorter ascospores and narrower ascospore septum.

Type: Denmark, Søborg par., the castle ruins 55.0877°N, 12.3055°E, on modern brick inclusions, 16.04.2023 Coll.: S.Y. Kondratyuk SK23721 – holo-type (C, voucher LD-M59 for nrITS); isotypes as set for the Plantae Graecenses exsiccate are prepared; SK23721B – isotype; SK23723, SK23723C, SK23722B sub Xanthoria pylyporlykii with Telogalla olivieri, SK23723D sub Xanthoria pylyporlykii with Athelia killing the centre and infected by Xanthoria sp. 1 (particularly on killed portions) (KW-L); SK23723E sub Xanthoria pylyporlykii infected by Xanthoria sp. 1, SK23723F sub Xanthoria pylyporlykii infected by Xanthoria sp. 1, SK23723G sub Xanthoria pylyporlykii infected by Xanthoria sp. 1, SK23723H sub Xanthoria pylyporlykii infected by Xanthoria sp. 1 (KW-L) – isotypes).

Thallus foliose, usually well developed and regularly rounded, of rather wide range from small to 3–5(–9) cm across, more or less rounded to widely oval / ellipsoid or forming much larger irregular aggregations; often with damaged, blackening or completely killed and collapsed central portions, forming film-like centre sometimes with distinct wrinkles or indistinct or covered with numerous apothecia, while lobes with reticulate upper surface are more or less developed only in the peripheral zone (without apothecia) to 5–7(–10) mm wide; sometimes brighter, yellow in the peripheral zone with the thicker and darker, greenish centre (distinctly greenish especially in wet conditions and very similar to Xanthoria calcicola) are rather different and contrasting, especially when the secondary, flat and horizontally orientated lobes are present in the centre; sometimes forming incomplete circles (‘arcs’) 1.5–2 cm wide and to 10 cm long, or wide circles (to 10–20 cm diam., where the central portion is completely collapsed) where narrow peripheral zone and numerous apothecia from the inner side of such circles are developed, similar to Kudratoviella anularis (Kondratyuk et al. 2023).

Thalline lobes thin, paper-like, 5–7(–10) long and 1–1.5(–2) mm wide in the narrowest portions while to 3–5(–7) mm wide in the widened terminal portions; sometimes secondary lobules are overlapping and irregularly orientated in the centre and well developed, somewhat ‘triangle’ to 1–1.5(–3) mm across forming variegated colouration owing bright yellow tips and well contrasting to darker greyish- or greenish-whitish towards the centre, somewhat raised above the thalline centre, horizontally orientated.

Thallus in section to (75–)100–140(–180) µm thick, upper cortical layer 5–7(–12) µm thick, sometimes irregularly developed, paraplectenchymatous, lumina to 5–7(–12) µm diam./across; algal zone to (25–)30–50(–70) µm thick, medullar layer to 50–70 µm thick, the lower cortical layer to 10–15(–20) µm thick, paraplectenchymatous with vertically slightly elongated cells.

Apothecia 1–3(–5) mm diam., in section to 0.2–0.3 mm thick from not very numerous, more or less distant, to rather numerous and crowded, usually distinct due to dark orange discs, contrasting the yellow thallus, more or less raised, lecanorine, initially with a permanent thalline margin, developing to zeorine or biatorine, discs more or less plane to slightly concave (reminding of Xanthoria calcicola), undulating at overmature, thalline margin distinctly raised above the disc giving the apothecia a concave impression, often becoming crenulate, or only in form of portions to distinctly zeorine, crowded at over-mature; in zeorine or biatorine apothecia: true exciple rather thin, permanent, concolorous with the disc or slightly lighter, rather distinct; in section, thalline exciple to 125 µm thick with cortical layer to 25–30 µm thick on underside; true exciple to 120–150 µm thick in the uppermost lateral portion and to 20–25 µm thick in the lower basal and basal portions; hymenium to 55–60 µm thick; ascospores sometimes with somewhat attenuated ends, more or less widened at the septa, (10–)11–15(–15.5) × 6–7.5(–8) µm, septa (5–)7–10 µm wide.

Conidiomata to 250–270 µm diam., hyaline, situated between the upper and the lower cortex of thallus; conidia very small ellipsoid, (1–)1.5–2.5(–3) µm.

Ecology: on rocky walls, tile roof of rock walls, on brick fragments of old ruins (Søborg, Hammershus castle ruins, etc.), often growing side by side with Xanthoria ectaneoides and growing together or overgrowing Physcia adscendens, Phaeophyscia orbicularis, etc. Xanthoria pylyporlykii is also confirmed from bark of Acer platanoides in coastal zone, so far only from a few localities in Æroskobing (SK23814, SK23815), Marstal (SK 23816, SK 23817) and Tranderup (SK23818), all within Ærø Island.

Xanthoria pylyporlykii is host for several lichenicolous fungi, e.g. Telogalla olivieri, Bryostigma parietinaria, Pyrenochaeta xanthoriae, Athelia arachnoidea, Xanthoriicola epiphysciae of which the first three are very common. The entire collection of Xanthoria pylyporlykii, 27 specimens at the locality Svendborg Landevej, southern Funen, and 23 specimens in Søby on Ærø were damaged by Telogalla olivieri, compared with only 30% in Fjenneslev, western Zealand. The number of infected specimens was much lower at other localities.

A rather high number of specimens of Xanthoria ectaneoides and X. pylyporlykii damaged by Telogalla olivieri was recently collected in Svaneke and Rønne on Bornholm.

Distribution: Xanthoria pylyporlykii is represented by more than 215 specimens from 44 localities around the western part of the Baltic Sea, i.e. in Skåne, southernmost Sweden, southern Denmark and northern Germany (Table 1, Fig. 9), however, it is probably distributed also in other Atlantic parts of Europe. Etymology: It is named after Pylyp Stepanovych Orlyk (11[21] October 1672–26 May 1742), author of the famous ‘Constitution of Pylyp Orlyk’, Hetman of Ukraine in-exile, secretary and close associate of Hetman Ivan Mazepa as well as his successor. Pylyp Orlyk lived in Kristianstad with his family after an official invitation from the Swedish king Karl XII. Latin version of ‘Constitution of Pylyp Orlyk’ with his signature is still kept in Sweden.

Taxonomic notes: After morphological characters Xanthoria pylyporlykii combines characters of Xanthoria ectaneoides in having Xanthoria coomae type of thallus and secondary lobules in the centre and Xanthoria calcicola in having greenish (especially in wet condition) centre, which is different from the peripheral zone.

Xanthoria pylyporlykii is similar to Xanthoria ectaneoides, its closest relative according to the phylogeny based on nrITS-sequences, however the new species usually differs in having a well-developed and regularly rounded thallus with a wider peripheral zone, (5–7(–10) mm wide vs. 1–3 mm wide in X. ectaneoides), in the lack of secondary sublobules (vs. especially numerous in the centre of X. ectaneoides); in having wider thalline lobes, usually well-developed, overlapping and irregularly orientated in the centre of the thallus, as well as and in having shorter ascospores with shorter septa.

Xanthoria pylyporlykii usually reminds of Xanthoria calcicola in having a dark greenish thallus centre wearing secondary lobes, but differs by much larger, flat and horizontally orientated secondary lobes with a smooth surface, as well as in having much wider ascospore septum.

Xanthoria pylyporlykii and Xanthoria coomae both have horizontally orientated, overlapping secondary lobes in the centre (Everöd, SK23498, SK23544, SK23545, SK23546), lobes developed only in the peripheral zone, however, X. pylyporlykii has a thinner thallus centre with a smooth surface (not wrinkled as in Xanthoria coomae). Furthermore, X. pylyporlykii differs by smaller, both narrower and shorter, and horizontally orientated thalline lobes in the narrower peripheral zone and in having shorter ascospores.

Two sequences in the GenBank, MT644879 and KJ027710, submitted as Xanthoria parietina probably represent Xanthoria pylyporlykii.

Selected specimens of Xanthoria pylyporlykii: Denmark, Søborg roof SK23723J, SK23723I sub Xanthoria pylyporlykii growing together with Xanthoria ectaneoides, SK23723K, SK23723L sub Xanthoria pylyporlykii, SK23723M, SK23723N, SK23723O, SK23723P, SK23723R. Paratype specimens of Xanthoria pylyporlykii from Søborg will be distributed as set of the Plantae Graecenses exsiccate. – Sweden, Skåne, Kristianstad municipality, Everöd, tile roof of rocky wall around church and cemetery, 4 March 2023 Coll.: S. Kond ratyuk SK 23498 (KW-L) sub Telogalla olivieri s.l. on rather damaged thalli of Xanthoria pylyporlykii with Xanthoriicola epiphysciae; SK 23499 (LD) (nrITS voucher LD-M77) sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1^***; SK 23498; SK23540 (voucher LD-M73 for nrITS), Everöd SK23569 (voucher LD-M75 for nrITS); Everöd SK23546 sub Xanthoria pylyporlykii with Athelia arachnoidea, SK23548 sub Xanthoria pylyporlykii with Telogalla olivieri, SK23554 sub Xanthoria pylyporlykii, growing side by side with Xanthoria ectaneoides, SK23555 sub Xanthoria ectaneoides, growing side by side with Xanthoria pylyporlykii, SK23556 sub Xanthoria pylyporlykii, growing side by side with Xanthoria ectaneoides. – Hel-singe, roof, 26.03.2023 SK23751 (nrITS voucher LD-M79); SK23741B LD-M79 voucher 742 sub Xanthoria pylyporlykii growing together with X. ectaneoides; SK23741 [7 of 8] sub 742] section 741 sub Xanthoria pylyporlykii and Xanthoria sp. 1^***, SK23741H [3 of 8], SK23741C [6 of 8], SK23741D [5 of 8] sub Xanthoria pylyporlykii with Athelia in places of the centre, SK23741E [4 of 8], SK23741G [1 of 8] sub Pyrenochaeta xanthoriae on Xanthoria pylyporlykii. SK23741 ‘B’ [8 of 8] section 742 = M79 sub Xanthoria pylyporlykii growing together with X. ectaneoides; Helsinge SK23747 (voucher for nrITS sequence LD-M55) sub Xanthoria pylyporlykii with Pyrenochaeta xanthoriae, and with small addition of Xanthoria ectaneoides. – Denmark, Søborg ruins SK23720; SK23720B; SK23720C sub Xanthoria pylyporlykii growing together with Xanthoria cf. ectaneoides; roof, SK23722 sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1. – Nexo, 28.10.2022 on separate rocks near rocky wall SK23716 (voucher LD-M53 for nrITS), SK23716B. – Helsinge 26.03.2023, tile roof of rocky wall Coll.: S. Kondratyuk SK23748 (voucher LD-M72 for nrITS) sub Pyrenochaeta xanthoriae on Xanthoria pylyporlykii [centre killed by lichenicolous fungus]; SK23749 (voucher LD-M54 for nrITS), SK23747 (voucher LD-M55 for nrITS) sub Xanthoria pylyporlykii with Pyrenochaeta xanthoriae, and with small addition of Xanthoria ectaneoides; 26iii2023 roof of eastern wall SK23751 (voucher LD-M71 for nrITS) sub Xanthoria pylyporlykii growing together with Xanthoria ectaneoides and partly infected by Xanthoria sp. 1. – ^***; SK23584 sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1. – ^***, SK23585 sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1. – ^*** and Telogalla olivieri, growing side by side with Physcia adscendens and Phaeophyscia orbicularis; SK23741G sub Xanthoria pylyporlykii with Pyrenochaeta xanthoriae. – Denmark, Søborg ruins SK23763 sub Xanthoria pylyporlykii with Telogalla olivieri, SK23764 sub Telogalla olivieri on Xanthoria pylyporlykii, SK23766B sub Xanthoria pylyporlykii with Telogalla olivieri, growing together with Xanthoria calcicola; SK23768C sub Xanthoria pylyporlykii with Telogalla olivieri and Xanthoria sp. 1. – ^***, SK23768E sub Xanthoria pylyporlykii with Telogalla olivieri; SK23595 sub Xanthoria pylyporlykii with Telogalla olivieri, two sets for the Plantae Gracenses exsiccate (one as Telogalla olivieri on Xanthoria pylyporlykii) with specimens of this collections (as SK23595B, SK23595C, SK23595D, etc) are prepared; SK23701 (voucher LD-M81 for nrITS) sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1^***; SK23701B [2 of 5] sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1^***; SK23701C [4 of 5] sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1^***, SK23701D [3 of 5] sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1^***, SK23701E [5 of 5] sub Xanthoria pylyporlykii partly infected by Xanthoria sp. 1^***. – Stehag SK23878 sub Xanthoria pylyporlykii with Telogalla olivieri, SK23885B sub Xanthoria pylyporlykii killed by Bryostigma parietinaria, SK23885E sub Xanthoria pylyporlykii damaged by Bryostigma parietinaria, and by Phoma sp., SK23893C sub Xanthoria pylyporlykii with Telogalla olivieri, SK23893D sub Xanthoria pylyporlykii with Bryostigma parietinaria, SK23890L sub Xanthoria pylyporlykii with Telogalla olivieri, Bryostigma parietinaria, [and other lichens], SK23890H sub Xanthoria pylyporlykii with Bryo-stigma parietinaria, [and other lichens], SK23897C sub Xanthoria pylyporlykii with Telogalla olivieri, SK23897D sub Xanthoria pylyporlykii with Telogalla olivieri. – Farum SK23495 sub Xanthoria pylyporlykii killed by Telogalla olivieri, SK23498 sub Xanthoria pylyporlykii with Telo galla olivieri, SK23509 sub Xanthoria pylyporlykii with Telogalla olivieri, SK23511 sub Xanthoria pylyporlykii with Telogalla olivieri, SK23512 sub Xanthoria pylyporlykii with Telogalla olivieri, growing side by side with Xanthoria ectaneoides; SK23534 sub Xanthoria pylyporlykii, growing side by side with Xanthoria ectaneoides; SK23535 sub Xanthoria ectaneoides, growing side by side with Xanthoria pylyporlykii; SK23536 sub Xanthoria pylyporlykii, growing side by side with Xanthoria ectaneoides; Farum 576 (nrITS voucher LD-M49). – Norra Vrams SK23492 sub Xanthoria pylyporlykii with Telogalla olivieri, SK23493 sub Xanthoria pylyporlykii with Telogalla olivieri. – Tofta SK23788D sub Xanthoria pylyporlykii with Athelia archnoidea. – Gørløse SK 23329 (voucher LD-M56 for nrITS). – Malmö 12.07.2022 SK22049 (section 49, and section 587) (voucher LD-M78 for nrITS), SK22049B, SK22049C. – Järavallen 9.06.2022, wood SK22046 (voucher LD-M66 for nrITS).

Xanthoria pylyporlykii in the Xanthoria coomae subclade known so far from Sweden, Denmark and Germany, is similar to X. ectaneoides but differs in having a more developed thallus with richly dissected thalline lobes and ascospores with narrower septa, is a rather common epilithic species in the investigated region growing side by side with Xanthoria calcicola. It is characterised by rather variegated to very large size thallus similar to the Xanthoria coomae type of thallus, with a more or less film like centre, and thalline lobes, developed only in the peripheral zone, with narrower and shorter thalline lobes than those characteristic for Xanthoria parietina, usually with numerous to very crowded apothecia as well as minute secondary thalline lobules in the centre of the thallus.

Molecular data from Xanthoria ectaneoides, X. ibizaensis and X. steineri are for the first time included in a phylogeny of the genus. Xanthoria ectaneoides and X. pylyporlykii were both revealed to belong to the Xanthoria coomae subclade of the genus.

Furthermore, representatives of Xanthoria steineri are included in the phylogenetic tree. The position of this species is based on nrITS sequences retrieved from whole genome data.