The Moss Genus Zygodon (Orthotrichaceae) in Poland – Distribution, Ecological Preferences and Threats

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The moss genus Zygodon (Orthotrichaceae) in Poland – distribution, ecological preferences and threats

Adam STEBEL a*&Jan ŻARNOWIEC b

aDepartment of Pharmaceutical Botany, Medical University of Silesia in Katowice, Ostrogórska 30, 41-200 Sosnowiec, Poland

bDepartment of Ecology and NatureProtection, University of Bielsko-Biała, Willowa 2, 43-309 Bielsko-Biała, Poland

Abstract – The moss genus Zygodon Hook. &Taylor (Orthotrichaceae) is represented by five species in Poland, namely: Z. dentatus (Limpr.) Kartt., Z. gracilis Wilson, Z. rupestris Schimp. ex A.W.H.Walth. &Molendo, Z. stirtonii Schimp. and Z. viridissimus (Dicks.) Brid. Their current distribution in Poland is reviewed and mapped, and lists of their localities are presented. The ecological preferences, altitudinal limits, reproduction and threats for each species are shortly discussed. Akey for determination of these species is given.

Bryophyta /Central Europe /moss diversity /epiphytes /phytogeography /protected mosses

INTRODUCTION

The genus Zygodon Hook. &Taylor includes small to medium-sized acrocarpous mosses forming light to dark green cushions, tufts, or rarely mats on trunks and branches of trees, logs, rarely on base-rich rocks, walls or on concrete. Brotherus (1925) placed in Zygodon 112species, and in the only world monograph Malta (1924, 1926) listed 77 species. Currently,itisbelievedthat the genus encompasses between 50 (Smith, 2004) and about 90-91 species (Crosby et al., 1999; Vitt, 2014). Zygodon is represented in the floras of both hemispheres in warm and temperate climates, but the highest species diversity is in the tropics and subtropics. The real species richness within this genus is most probably lower,because modern taxonomic revisions show,that anumber of species have been described repeatedly under various names. For example, Calabrese (2006) described one new species and accepted 12 taxa from 20 known from South America, the names of the remainder being reduced to synonymy.For Australasia and Australia, six species are recognised (Lewinsky,1990; Lewinsky-Haapasaari &Ramsay,2012), and in the moss flora of North America five species and two varieties (Z. viridissimus (Dicks.) Brid. var. rupestris Lindb. and Z. viridissimus var. dentatus Limpr., frequently considered as

* Corresponding author: [email protected]

doi/10.7872/cryb/v38.iss3.2017.231 232 A. Stebel &J.Żarnowiec separate species) are mentioned (Britton, 1908; Vitt, 2014). Düll (1985a) revised European specimens of Zygodon,and new conceptualisations of the genus are represented in the modern Floras (e.g. Lewinsky-Haapasaari, 1998; Smith, 2004). In total, nine species and one variety are now recognised from Europe (Hill et al., 2006; Garcia et al.,2006), of which five species are represented in Poland (Ochyra et al., 2003; Stebel et al. in Blockeel et al.,2007). The aims of this paper are to address the following: (i)what is the present diversity of Zygodon in Poland? (ii) what is their geographical distribution? (iii) what is their altitudinal range? (iv) what are their habitat preferences? and (v) is their occurrence in Poland threatened?

MATERIALS AND METHODS

All available collections of Zygodon from Poland (over 80 specimens) from the following herbaria: KRAM, LBL, OSTR, POZG, SOSN, WA,and WRSL, were re-examined. Additional field research during the last few years was also conducted and collected specimens are housed in the herbarium SOSN. The overwhelming majority of localities known from the literature were revisited. In earlier papers, especially from northern Poland, information about the occurrence of Z. viridissimus s.l. is presented (e.g. Koppe, 1931; Dietzow,1938). Because of the lack of specimens, these data have not been included in the analysis. All information about habitat, altitude, and others, was included in adata base. The data gathered during fieldwork and the information contained on herbarium labels formed the basis for description of the ecological preferences of these taxa. For microscopic examination, dried plants were soaked in water and permanent slides of leaves, sections and propagula were mounted in Hoyer’s solution (Anderson, 1954), and the species have been distinguished on the basis of morphological characters. All measurements were obtainedfrom wet plants and/or from prepared slides mounted in Hoyer’s solution. Morphological and anatomical details were drawn with the aid of aNikon Eclipse E200 compound microscope and Nikon Y-IDT drawing tube. The distributions of the individual taxa have been presented as dot maps. The signatures of sites were split into five time phases. Analysis of species occurrence was undertaken using five time periods to show historical trends for individual taxa over the last decades. For each species the list of known stations are presented. For literature based records the bibliographical information is included. New findings and localities not known from literature are marked with an asterisk. For allocation of individual species to each threat category the latest IUCN criteria (IUCN, 2012 – second edition of version 3.1, first published in 2001) have been used, with recommendations for estimating threatened taxa (IUCN Standards and Petitions Subcommittee, 2014) and Guidelines for application of IUCN Red List criteria at regional and national levels (IUCN, 2010), adapted for bryophytes (Hällingbäck et al.,1998; Hodgetts, 2015). Some species elaborated in this paper,including Zygodon dentatus (Limpr.) Kartt.,Z.rupestris Schimp. ex A.W.H.Walth. &Molendo and Z. stirtonii Schimp.are treated at alower taxonomic rank, mainly as varietes of Z. viridissimus (e.g.Düll, 1992;Frey et al.,2006; van der Pluijm, 2012; Vitt, 2014), but, following Karttunen (1984), Smith (2004)and Hill et al. (2006),weview them as separate species. Zygodon in Poland 233

RESULTS

In Poland, five species of Zygodon occur,namely: Z. dentatus, Z. gracilis, Z. rupestris, Z. stirtonii and Z. viridissimus.All belong to sect. Zygodon and subg. Zygodon.They are small acrocarpous mosses forming loose turfs or soft cushions on trunks and branches of trees, more rarely on calcareous rocks, on light-shaded walls and on concrete. Their main features are erect, simple or branched stems; lanceolate to linear-lanceolate leaves with and acute apex; margins entire or denticulate towards the apex and plane or recurved below; costa vanishing below the leaf apex or rarely excurrent; lamina cells quadrate, rounded-hexagonal to ovate; upper lamina cells papillose; and rectangular,smooth, translucent basal lamina cells. In leaf axils are frequently present ovoid to ellipsoidal gemmae. Polish Zygodon taxa are dioicous but in all examined materials only twice were afew archegonia observed (in Z. rupestris and Z. viridissimus). Also twice, in the same species, immature and broken sporophytes were noted.

Key for identification Polish species of Zygodon 1. Margin of upper leaves toothed towards apex; plants without gemmae, only on limestone rocks...... Z. gracilis 1. Margin of leaves entire or,particularly in young leaves, denticulate near apex; plants with gemmae, growing mainly on bark of trees...... 2 2. Gemmae without cross-walls ...... Z. rupestris 2. Gemmae with cross-walls ...... 3 3. Margin of younger leaves usually denticulate near apex; gemmae with curved cell-walls...... Z. dentatus 3. Margin of leaves entire; gemmae with almost straight cell-walls...... 4 4. Costa distinctly widened in leaf apex, excurrent in asharp, stout point ...... Z. stirtonii 4. Costa not widened in leaf apex, percurrent or subpercurrent...... Z. viridissimus

Asurvey of species

Zygodon gracilis Wilson Figs 1-5, 38 Plants (1.0-)1.5-3.5(-5.0) cm high, forming brownish to yellowish-green to dark-green tufts. Leaves lanceolate to oblong-lanceolate,pointed, contorted and incurved when dry,spreading to recurved when moist. Margin of the upper leaves sharply serrate towards the apex, entire below.Costa stout, ending below or in the apex. Mid-lamina cells rounded-hexagonal, thick-walled, (4-)7-9(-10) µmwide with (1-)2-4 clavate papillae. Fertile plants not observed in Polish material. General distribution. — Zygodon gracilis occurs sporadically in the Carpathians and frequently in the Alps (Düll, 1985a, b; Frey et al.,2006; Meinunger &Schröder,2007; Müller,2005). Elsewhere it is reported from mid-west Yorkshire in England (Proctor &Blockeel,2014a), British Columbia in North America and from one locality in Guatemala in Central America (Vitt, 2014), but Central American plants apparently belong to Z. campylophyllus Müll.Hal. (Allen, 1994). 234 A. Stebel &J.Żarnowiec Zygodon in Poland 235

Extent of distribution and altitudinal range in Poland. — Previously reported from Poland under the name Zygodon gracilis var. alpinus (Schimp.) Grav. (Lisowski, 1960a, 1962). The species is known from only one locality in Dolina Kościeliska valley situated in the western part of the Tatras at an altitude 1050- 1090 m(Fig. 38). Ecology. — Grows on limestone on open dry outcrops by mountain streams, together with such species, as Ctenidium molluscum (Hedw.) Mitt., Ditrichum flexicaule (Schwägr.) Hampe, Neckera crispa Hedw., Plagiobryum zieri (Hedw.) Lindb., Tortella tortuosa (Hedw.) Limpr.and others.

Fig. 38. Distribution of Zygodon gracilis in Poland.

Figs 1-37. Morphological details of Polish species of Zygodon. Zygodon gracilis Wilson – 1-3. Leaves. ▲ 4. Leaf apex. 5. Mid-leaf cells. Z. viridissimus (Dicks.) Brid. – 6-8. Leaves. 9. Leaf apex. 10. Mid- leaf cells. 11-16. Gemmae. Z. stirtonii Schimp. – 17, 18. Leaves. 19. Leaf apex. 20. Mid-leaf cells. 21-23. Gemmae. Z. dentatus (Limpr.) Karttunen – 24, 25. Leaves. 26. Leaf apex. 27. Mid-leaf cells. 28-30. Gemmae. Z. rupestris – 31, 32. Leaves. 33. Leaf apex. 34. Mid-leaf cells. 35-37. Gemmae. [1-5 from Lisowski s.n.,Tatras, 1960, sosn;6-16 from Stebel s.n.,Wolin Island, 2014, sosn;17-23 from Salachna s.n.,Wolin Island, 2014, sosn;24- 30 from Armata s.n.,Bieszczady Mts, 2004, sosn;31-37 from Armata s.n. Bieszczady Mts, 2003, sosn]. Scale bars: a – 1mm(1-3, 6-8, 17, 18, 24, 25, 31, 32); b – 100 µm(4, 9, 11-16, 19, 21-23, 26, 28-30, 33, 35-37); c – 100 µm(5, 10, 20, 27, 34). 236 A. Stebel &J.Żarnowiec

Threats. — Zygodon gracilis is an exceedingly rare species in Poland known from one locality,where it in has been discovered in 1960 by Lisowski (1960a, 1962). This locality was visited and confirmed in 2007 by the junior author. The small known population of the moss is located near abusy tourist trail and thus it could be strongly threatened by tourist pressure and by collectors of plants. Considering its geographical range, single known locality and small size of the population, the threat category of Z. gracilis should be assessed as Critically Endangered CR [B2ab(ii,iii)]. Notes. — Zygodon gracilis var. alpinus is an ecotype characterised by the larger size of stems and longer,broader leaves, but without taxonomic significance (Ochyra et al.,2003). In the Carpathians Z. gracilis is only known in Poland and Slovakia (Kubinská et al.,2001). Information about its occurrence in the Southern Carpathians in Romania (Ştefǎnut &Goia, 2012) is doubtful and based probably on erroneous data (pers. comm. from S. Ştefǎnut – 13 April 2016). Mohan (2015), in the latest Moss Flora of Romania, did not include this rare species. List of localities. — Western Carpathians. Tatra:Dolina Kościeliska valley, Raptawicka Turnia, 1070 m(leg.S.Lisowski, 19 Aug 1960, KRAM, POZG, SOSN; Lisowski, 1960a, 1962; leg.J.Żarnowiec, 6Feb 2007, KRAM, SOSN). Zygodon viridissimus (Dicks.) Brid. Figs 6-16, 39 Plants to 1.0-1.5 cm tall in tufts or cushions, light-brown below and olive- green above. Stems erect, usually simple, more rarely branched. Shoots often curved upwards when dry.Leaves twisted when dry,erect-spreading when moist, lanceolate to oblong-lanceolate, weakly keeled, apex acute, with ashort apiculus of 1-2 cells. Leaf margins plane, entire. Costa vanishing below the apex. Mid-leaf cells thick- walled, rounded-hexagonal, 6-11(-13) µmwide, papillose, papillae simple, blunt, (2-)3-4(-5) per cell. Gemmae clavate, ovoid to elliptic, consisting of (4-)6-9 cells, with transverse and longitudinal septae, cell walls hyaline to yellowish-brown. Dioicous. Archegonia were observed only in the specimen from Wisełka village on Wolin Island (leg. S. Lisowski, 18.09.1956) and afew very young sporophytes were found only in the collection from Międzyzdroje town on Wolin Island (leg. J. Winkelmann, 1886). General distribution. — Zygodon viridissimus is scattered throughout Europe, from the Iberian Peninsula (Calabrese &Muñoz, 2008), British Isles (Proctor &Blockeel, 2014b), north to Fennoscandia (Lewinsky-Haapasaari, 1998), east to the European part of Russia, Russian part of the Caucasus, Georgia, Azerbaijan (Ignatov et al.,2006), south-east to Romania and Greece (Sabovljević et al.,2008). It is also known from Iceland (Lewinsky-Haapasaari, 1998) and Macaronesia (Düll, 1985b; Smith, 2004), Russian South Far East (Ignatov et al.,2006) and Japan (Lewinsky- Haapasaari, 1998). In North America it is reported from the eastern part of Canada in Quebec and Nova Scotia (Vitt, 2014). Extent of distribution and altitudinal range in Poland. — This species was previously reported from Poland under the name Zygodon viridissimus var. occidentalis Malta (Lisowski, 1957b, 1961). Zygodon viridissimus is known from nine localities – eight from Western Pomerania and one from Eastern Pomerania (Fig. 39). The easternmost site of this species lies in Jurata on the Hel Peninsula. The highest concentration of its localities is on Wolin Island (over half of the stations), where for the first time it was found by Winkelmann in 1886. The lowest altitude localities of Z. viridissimus are in the vicinity of the Jurata (ca 10 ma.s.l.) on the Hel Peninsula, while the highest is near Otrzep (ca 140-150 ma.s.l.) in the Drawsko County. Zygodon in Poland 237

Fig. 39. Distribution and ecological preferences of Zygodon viridissimus in Poland. 238 A. Stebel &J.Żarnowiec

Ecology. — All known stations are on the area influenced by humid air masses from the Atlantic and Baltic Sea. Almost 92% are as epiphytes on bark of trees with only one found on the concretewall of old bunker.Most frequently it grew in light-shade conditions in beech forest (66.7% specimens), rarely in mixed forests (16.6%) and on wayside trees (16.6%). Zygodon viridissimus was noted on four host-trees, most frequently overgrowing bark of beeches (45.5%), frequently on oaks (27.3%), rarely on Scotch-pines (18.2%) and apple trees (9.1%) (Fig. 39). When found on Pinus sylvestris L. it occurred on dust and sand deposits on the bark of the roots protruding from the soil and lower part of trunks. It was associated with such species, as Dicranella heteromalla (Hedw.) Schimp., Hypnum cupressiforme Hedw., Orthodicranum montanum (Hedw.) Loeske, Neckera complanata (Hedw.) Huebener and Zygodon stirtonii. Threats. — Zygodon viridissimus was observed on at seven stations over 50 years ago, one 28 years ago and in 2014 twice on closelylocatedstations on the Wolin Island. It forms small turfs. The main factors reducing its occurrence are air pollution and diminishing old growth, natural forest complexes. In the light of the current data Z. viridissimus should be classified as Endangered moss EN [B2ab(i,ii,iii,iv)]. List of localities. — Western pomerania. Wolin Island:near Wisełka village (leg.S.Lisowski, 18 Sep 1956, KRAM, LBL, POZG, WRSL; Lisowski, 1957b – Bryotheca polonica No. 461; Mickiewicz, 1965); *Międzyzdroje (leg.Winkelmann, 18 Jul 1886, POZG), plants with young sporophytes (leg. R. Ruthe; Limpricht, 1895); near Międzyzdroje (leg.J.Duda, 18 Jun 1958, WA); same locality (leg. J. Mickiewicz, s. dato,WA; Mickiewicz, 1965); *near Kawcza Góra hill (leg.Winkelmann, Jul 1886, POZG, with young sporophytes); *Świdna Kępa hill (leg.S.Lisowski, 8Nov 1957, POZG); between Świdna Kępa and Gosań hills (leg.A.Stebel, 13 Sep 2014, KRAM, SOSN and leg.G.Vončina, 13 Sep 2014, SOSN; Wilhelm et al., 2015). Wzniesienia Szczecińskie:Szczecin-Osowice(leg.Winkelmann, May 1892, POZG; Winkelmann, 1893); *Otrzep (leg.F.Hintze, 11 Sep 1903, POZG). Pojezierze Drawskie:*Łabędzie near Drawsko (leg.F.Hintze, 22 Aug 1932, KRAM, LBL, SOSN). eastern pomerania. Mierzeja Helska:Jurata, concrete wall of old bunker (leg. R. Ochyra 348/81, 3Jun 1981, KRAM; Ochyra, 1988). Zygodon stirtonii Schimp. Figs 17-23, 40 Plants to 0.7-1.0 cm high in loose tufts, yellow-brown below and dark- green above. Stems erect, simple, rarely branched. Leaves twisted when dry, spreading when moist, narrowly lanceolate, keeled, apex acute. Margins of leaves plane, entire, lamina usually ending asymmetrically at the apex. Costa widened in the upper part of the leaf and excurrent in astout mucro. Mid-lamina cells isodiametric, incrassate, rounded-hexagonal, 7-10 µmwide, papillose, papillae simple, blunt (2-)3-4 per cell. Propagula hyaline to yellowish-brown, of 5-9 cells, clavate, with transverse and longitudinal septa. Gametangiaand sporophytes were not found in Poland. General distribution. — Zygodon stirtonii is arare European endemic moss with oceanic distribution (Düll, 1985a, b, 1992). It grows mainly close to the sea shore in areas of north-western Europe. It is known from Cantabria province in northern Spain (Calabrese &Muñoz, 2008), through the British Isles (Smith, 2004), Trondheim province in the middle of Norway (Hassel, 2010), southern Sweden (Lewinsky-Haapasaari, 1998), Finland, Estonia (Hodgetts, 2015) and Poland (Stebel et al. in Blockeel et al.,2007). The highest concentration of its stations is in the Netherlands (van der Pluijm, 2012) and Germany (Meinunger &Schröder,2007). Extent of distribution and altitudinal range in Poland. — The species is known exclusively from Wolin Island, the north-westernmost part of Poland Zygodon in Poland 239

Fig. 40. Distribution of Zygodon stirtoni in Poland.

(Fig. 40). For the first time it was found here in the 1950’sbyLisowski (Stebel et al. in Blockeel et al.,2007). Recent investigations brought two new discoveries of this moss. Its stations lie at an altitude of 20-50 m. Ecology. — Three known stations of Zygodon stirtonii lay close to the sea shore, in the area with amaritime climate in close proximity to the Baltic Sea. It occurred in patches of beech forest with loose stands and overgrew bark of Quercus petraea (Matt.) Liebl. and the snag and trunk of living Fagus sylvatica L. Specimens were associated with such species as Dicranella heteromalla, Hypnum cupressiforme, Neckera complanata and Zygodon viridissimus. Threats. — At present Zygodon stirtonii is known from two closely lying stations on Wolin Island. The population was small with only several scanty turfs, covering about 2-10 cm2.Ithas grown here probably continuously for sixty years and its stations are protected within the Wolin National Park. The potential threats may only be natural (e.g., destruction of the stand by storm or fire). However,due to its rarity and small size of the population, the threat category should be estimated as Critically Endangered CR [B2ab(i,ii,iii,iv); D1]. Notes. — Zygodon stirtonii has been reported from Romania (Düll, 1985b; Sabovljević et al.,2008; Ştefǎnut &Goia, 2012), but this information needs 240 A. Stebel &J.Żarnowiec confirmation (pers. comm. from S. Ştefǎnut – 3April 2016). In the recent moss flora of Romania (Mohan, 2015) this taxon is not included. Zygodon stirtonii twice occurred with Z. viridissimus but, similar to the observation of van der Pluijm (2012) in the Netherlands, plants with intermediate features between the two taxa were not observed. List of localities. — Western pomerania. Wolin Island:near Wisełka village (leg.S.Lisowski, 8Nov 1957, POZG; Stebel et al., 2007); near Gardno lake (leg. A. Salachna, 12 Sep 2014, KRAM, SOSN & leg. S. Wierzcholska, 12 Sep 2014, SOSN; Wilhelm et al., 2015); between Świdna Kępa and Gosań hills (leg.A.Stebel, 13 Sep 2014, KRAM, SOSN and leg.R.Zubel, 13 Sep 2014, LBL; Wilhelm et al., 2015). Zygodon dentatus (Limpr.) Kartt. Figs 24-30, 41 Plants to 1.5 cm tall in light-green tufts or soft cushions. Stem leaves oblong-lanceolate to narrowly lanceolate, spreading when moist, usually ending with ashort apiculus, sharply pointed. Margins of leaves plane, irregularly dentate near the acute apex. Costa vanishing below apex. Mid-lamina cells isodiametric, 6-8(-10) µmwide, incrassate, strongly papillose with (2-)3-4(-5) papillae per cell. Gemmae in clusters, in axils of leaves, compound of (4-)5-7(-9) cells with curved longitudinal cell-walls. In Polish collections gametangia and sporophytes are unknown. General distribution. — Zygodon dentatus is arare mountain species mainly distributed in Central European mountains, i.e. Carpathians and Alps (Karttunen, 1984; Düll, 1985b; Frey et al.,2006). Elsewhere it has been reported from one locality in Telemark in southern Norway (Lewinsky-Haapasaari, 1998), from Georgia (Ignatov et al.,2006) and from the White Mountains in Arizona, U.S.A. (Vitt, 2014). Extent of distribution and altitudinal range in Poland. — Zygodon dentatus was reported for the first time in Poland by Lisowski (1957a) from one locality situated in the Bieszczady Zachodnie range. Szafran (1961) considered it as Z. viridissimus subsp. dentatus (Breidl.) J.J.Amann in his moss flora of Poland. Zygodon dentatus is only known in the Carpathians Mts and Sudetes Mts in southern Poland (Fig. 41). It has been discovered in various parts of the Carpathians, and it is currently known from 23 stations there. In the Sudetes, the second mountain chain in Poland, Z. dentatus is known from only one recently discovered locality in the Góry Bialskie range (Wierzcholska &Plášek, 2006). The lowest site of the species lies at altitude of 440 minthe Beskid Wysoki range, whereas the highest at 1120 m in the Tatras. It is closely related with lower forest belt. In total, 75.0% stations of Z. dentatus lie between 601 and 1100 m. Ecology. — Z. dentatus is an obligatory epiphytic species. 88.5% of the specimens have been collected from the bark of living trees and 11.5% on bark of decaying logs. Among the host-tree species, Fagus sylvatica was preferred (73.1%), rarely it occurred on willows (Salix alba L. and S. fragilis L.) (11.5%), and sporadically on Fraxinus excelsior (7.7%) and Acer pseudoplatanus L. (3.8%) and A. platanoides L. (3.8%) (Fig. 41). The majority of its stations are within forest communities (86.9%), rarely it occurs on wayside and solitary trees (13.1%). The first findings of this moss originated from well-preservedforest areas, exclusively from the bark of beech growing in old stands. Only recently in afew cases has it been found on bark of wayside trees. It has been collected associated with such species, as Anomodon viticulosus (Hedw.) Hook. &Taylor, Hypnum cupressiforme, Neckera complanata, Orthodicranum montanum and Isothecium alopecuroides (Dubois) Isov. Zygodon in Poland 241

Fig. 41. Distribution and ecological preferences of Zygodon dentatus in Poland. 242 A. Stebel &J.Żarnowiec

Threats. — Although Zygodon dentatus is known from 24 stations, it is a very rare species in the bryoflora of Poland. About 61% of collections were made over 60 years ago, and in the last 25 years it has been found only 9times. Its local populations were scanty and most frequently covered only several square centimetres. The typicalhabitatofZ. dentatus old beech forest, the area of which is still decreasing. Considering this information, Z. dentatus should be classified in the category Vulnerable VU [B2ab(i,iii,iv); D2]. List of localities. — sudetes. Góry Bialskie:Stronie Śląskie, 470 m(leg. S. Wierzcholska &V.Plášek, Jul 2004, OSTR; Wierzcholska &Plášek, 2006). Western Carpathians. Beskid Śląski:Wisła, BiałaWisełka stream valley,720 m (Mickiewicz, 1965); Czarna Wisełka stream valley (Mickiewicz, 1965). Beskid Makowski: Koszarawa, 590 m(leg.A.Stebel, 9Jun 2000, SOSN; Stebel, 2006). Beskid Wysoki: Węgierska Górka, 440 m(leg.B.Kowalczyk, 19 Aug 1996, SOSN; Stebel, 2006); Babia Góra massif:Hala Czarnego, 980 m(Mickiewicz, 1965); Mokry Stawek, 1000 m(Mickiewicz, 1965); forest sections No 14g, 1080 m, No 15, 1000 mand No 16, 875 m(Szukalska, 2007); Pilsko massif:Hala Buczynka, 1180 m(Lisowski, 1960b); Polica range:*Zawoja-Widły, 720-750 m(leg. R. Ochyra 2206/78, 28 Jul 1978, KRAM). Gorce:Turbacz mountain, northern slope (formerly Orkana nature reserve) (Mickiewicz, 1965); same locality,980 m (Lisowski &Kornaś 1966) and 1100 m(leg.S.Lisowski, 22 Oct 1956, KRAM, POZG; Lisowski, 1956c – Bryotheca polonica No. 336); Turbaczyk mountain, 1030 m(Lisowski & Kornaś,1966); Łopuszna stream valley,slope below Mt Turbacz, 1005 m(leg.S.Lisowski, 1Apr 1959, POZG; Lisowski &Kornaś,1966); *Czubaty Groń mountain, north-west of summit, 957 m(leg. A. Stebel, 15 Jul 2014, KRAM, SOSN). Beskid Sądecki:Makowica mountain (Mickiewicz, 1965). Tatra:*Wielki Kopieniec mountain, western slope, 1120 m (leg.S.Lisowski, 9Aug 1966, POZG) and north-western slope, 1060-1100 m(Mickiewicz, 1965); *Zakopane-Kuźnice,995 m(leg.A.Stebel, 22 Jun 2012, KRAM, SOSN). eastern Carpathians. Góry Sanocko-Turczańskie:*Góra Stop near Wańkowa, 458 m(leg. G. Vo nčina, 1May 2016, KRAM). Bieszczady Zachodnie: Dział mountain, 720 m(leg.S.Lisowski, 24 Apr 1956, POZG; Lisowski, 1956a-b as Leptodontium styriacum;Lisowski, 1957a), Moczarne village, above Górna Solinka stream, 675 m(leg.L.Armata, 16 Jul 2004, KRAM, LBL, SOSN; Armata, 2006); MałaRawka mountain, south-western slope (Mickiewicz, 1965);Wyżyna (= Magura) Stuposiańska mountain, south-eastern slope (Mickiewicz, 1965). Zygodon rupestris A.W.H.Walth. &Molendo Figs 31-37, 42 Plants to 1.7 cm high, in loose tufts, yellow-brown below and green to olive-green above. Stems erect,simple or branched. Leavestwisted when dry and erect-spreading when moist, lanceolate to linear-lanceolate, keeled, apex with ashort apiculus of 1-2(-3) cells. Margins of leaves plane, entire. Costa ending below apex. Mid-lamina cells rounded-hexagonal, thick-walled, 7-9(-12) µmwide, with 3-5(-6) low,blunt papillae per cell. Propagulae abundant in the leaf axils, elliptic of (3-)4-6 cells, with hyaline to yellowish-brown transverse walls, cross-walls absent. Dioicous. In examinedmaterial, only in aspecimencollected near Mieszkowice in north-west Poland (leg. R. Ruthe, s.dato)were archegonia found, and in acollection from Czasław near Dobczyce in south of Poland (leg. A. Żmuda, 1.05.1910) two plants with broken-offsporophytes were noted. General distribution. — Zygodon rupestris is distributed throughout Europe and is quite common in some areas, especially in the southern part of the continent (Karttunen, 1984; Düll, 1985b; Frey et al. 2006). It ranges from the Iberian Peninsula (Calabrese &Muñoz, 2008), through Ireland and Great Britain (Proctor &Blockeel, 2014c), north to Fennoscandia (Lewinsky-Haapasaari, 1998), east to the Russian European north-west and the Russian Caucasus (Ignatov et al. 2006). It is widespread in South-East Europe from Slovenia to Romania and to European Turkey Zygodon in Poland 243

Fig. 42. Distribution and ecological preferences of Zygodon rupestris in Poland. 244 A. Stebel &J.Żarnowiec

(Sabovljević et al.,2008). The species has also been reported from Macaronesia, North Africa, Central Asia and from Japan (Düll, 1985b; Lewinsky-Haapasaari, 1998; Smith, 2004). In North America it is present from Mexico to Alaska (Vitt, 2014). Extent of distribution and altitudinal range in Poland. — Zygodon rupestris was previously reported from Poland under the name Zygodon viridissimus var. vulgaris Malta (Malta, 1924; Lisowski, 1961). It is the most widely distributed representative of the genus Zygodon in Poland (Fig. 42). 52.3% of its stations lie in the lower forest belt in the mountains (Carpathians and Sudetes) whereas 47.7% were noted from lowlands and highlands. The lowest site for the moss is at about 20 maltitude in the Pomerania region, whereas the highest is 1150 minthe Tatras. Ecology. — Zygodon rupestris is an epiphytic species and 95.5% of studied specimens were noted from bark of trees (2.3% grow on rocks and 2.3% alack substrate information). Most frequently it overgrew bark of Fagus sylvatica (61.4%), rarely Salix alba and S. fragilis (9.1%), Quercus spp. (6.8%), Fraxinus excelsior (4.5%) and Ulmus glabra Huds. (4.5%), with sporadic occurrence on other trees (Fig. 42). It was noticed in forest complexes (79.5%), rarely in open areas (20.5%). The earliest collections originated from well-preserved old growth beech forests. Afew recent collections are from bark of wayside trees. The most common associates are Hypnum cupressiforme, Neckera complanata, Orthodicranum montanum, Pterigynandrum filiforme Hedw.and others bryophytes. Threats. — Zygodon rupestris is known from 44 stations, but in the last 15 years it has been observed only at 13. Usually its subpopulations covered small areas and were dispersed. It prefers old beech stands, the area of which is still decreasing, but recently it is more and more frequently being observed on wayside and solitary trees. In the light of these data, Zygodon rupestris should be classified to the category Near Threatened(NT). Listoflocalities. — Western pomerania. Wolin Island:*Gardno lake (leg. S. Wierzcholska, 12 Sep 2014, SOSN); *Sośnica village (leg.F.Roemer,4Oct 1904, KRAM and leg. F. Hintze, 12 Nov 1897, KRAM); Otrzep village (Malta, 1924); Steknica village, near railway station (Mickiewicz, 1965); Tuchola Forest National Park, west of Wielkie Gacno lake (leg.A.Stebel, 4Aug 2001, SOSN; Stebel, 2012); *Mieszkowice (leg.R.Ruthe, s. dato,KRAM); *Mechowo near Puck,outcrop of Pleistocene sandstone called “Grota Mechowska” (leg. M. Szczepański 8282, 23 Aug 2009, KRAM). masuria. Puszcza Romincka:*Boczki reserve (leg. S. Wierzcholska, 17 Sep 2016, KRAM). podlasie. Nizina Podlaska, BiałowieżaNational Park:*forest section No 256 (leg.J.Żarnowiec,20Oct 1988 and 25 Apr 1989, SOSN; Żarnowiec 1992 as Z. viridissimus); *Narewka river valley near ‘Budnicka Droga’ (leg.S.Wierzcholska &A.Stebel, 30 Aug 2016, SOSN); *Czerlonka (leg.E.Pszczółkowska, 4Jul 1969, WA). sudetes. Góry Kamienne:Rogowiec mountain, 720 m(Mickiewicz, 1965). silesian upland. Rybnik-Ochojec (leg.R.Fritze, Oct 1870, Limpricht, Bryotheca Silesiaca No 315; leg.R.Fritze, Apr 1874, KRAM, WRSL; Milde, 1870a, basZ. viridissimus; Malta, 1924). Western Carpathians. Pogórze Wiśnickie:Czasław (leg.A.Żmuda, 1May 1910, KRAM). DołyJasielsko-Sanockie:Krosno, 300 m(leg.L.Armata, 21 Jul 2006, KRAM, LBL, SOSN; Armata, 2008); Sanok-Olchowce, 325 m(leg.L.Armata, 21 Jul 2005, KRAM, LBL, SOSN; Armata, 2008). Beskid Śląski:Wisła, BiałaWisełka stream valley,720 m (Mickiewicz, 1965); between Wisła-Czarne and Kubalonka pass (Mickiewicz, 1965). Beskid Wysoki: Babia Góra massif:near Hala Czarnego, 1000 (Mickiewicz, 1965); below Czarna Hala, 965 m(leg.A.Stebel, 24 Aug 1999, SOSN; Stebel, 2006); near Markowy Potok stream (Mickiewicz, 1965). Beskid Wyspowy:Olszanka village, near the Jastrząbka stream, 383 m(leg.A.Stebel, 11 Jul 2001, SOSN; Stebel, 2006). Gorce:Turbacz mountain, northern slope (formerly Orkana Nature Reserve), 995 m, 1000 mand 1025 m(leg.S.Lisowski, Zygodon in Poland 245

1Apr 1959, POZG; Lisowski &Kornaś,1966) and 800-900 m(Mickiewicz, 1965); same locality,southern slope, 1100 m(Mickiewicz, 1965); Mostownica mountain, eastern slope, 1100 m(leg.S.Lisowski, 3Apr 1959, KRAM, POZG, SOSN;Lisowski, 1959 – Bryotheca Polonica No. 1088; Lisowski &Kornaś,1966); Kudłoń mountain, near Polana Przysłopek mountain pasture, 1110m(Lisowski &Kornaś,1966); *Poręba Wielka, old park, 505 m(leg.A.Stebel, 12 Aug 2013, KRAM, SOSN). Beskid Sądecki: Makowica mountain, slope near the ruins of the castle in Rytro (Mickiewicz, 1965); Wzniesienie Spisko- Gubałowskie:*Kacwin, near the Kacwinka stream, 590 m(leg.R.Ochyra &A.Stebel, 4Jun 2008, KRAM, SOSN). Tatra:Dolina Ku Dziurze valley,1000 m(Mickiewicz, 1965); Dolina Strążyska, 1100 m(Mickiewicz, 1965); Wielki Kopieniec mountain, western slope, 1100 m(Mickiewicz, 1965); Dolina Białego valley,1020 m(leg.S.Lisowski, 11 Jul 1965, POZG; Lisowski, 1965 – Bryotheca Polonica No. 1814), *slopes towards Przełęcz Białego, 1080 m(leg. S. Lisowski, 18 Apr 1966, POZG), *below Przełęcz Białego, 1150 m(leg. S. Lisowski, 8Aug 1966, POZG). eastern Carpathians. Góry Sanocko-Turczańskie:*ChwaniówNature Reserve, south of Średni Garb mountain, 592 m(leg.A.Stebel, 10 Oct 2015, KRAM, SOSN); *Na Opalonym Nature Reserve, near the Turzański stream, 482 m(leg.A.Stebel, 30 Jul 2015, SOSN); *Góra Stop near Wańkowa, 458 m(leg. G. Vončina, 1May 2016, KRAM). Bieszczady Zachodnie:Falowa mountain, south-western slope (Mickiewicz, 1965); Dział mountain, slope near the Solinka river,780-800 m(Mickiewicz, 1965) and south-western slope, 800 m(leg.L.Armata, 5Aug 2003, KRAM, LBL, SOSN; Armata, 2006); Wyżyna (= Magura) Stuposiańska mountain, south-eastern slope, 620-700 m(Mickiewicz, 1965); *near Dwerniczek village (leg.W.Berdowski, 25 Jul 1964, POZG).

DISCUSSION AND CONCLUSIONS

The location of Poland between Western and Eastern Europe is reflected in the species richness within the genus Zygodon,which clearly decreases from west to east and south. This is caused by adeclining influence of humid air masses from the Atlantic Ocean and an increasing influence of the continental climate. In Poland five species of Zygodon occur,whereas in adjoining Germany to the west, seven species are known. To the south – Czech Republic three and Slovakia three, from east – the Ukraine three, Lithuania – two, while in Belarus and the Russian Kaliningrad Province, there are no species known (Table 1). One additional species, Z. conoideus (Dicks.) Hook. &Taylor,was reported in the early stages of the bryological research in Poland, from Beskid Śląski range in the Western Carpathians (Milde, 1852), but its occurrence is erroneous (Ochyra et al.,2003). Species of the genus Zygodon are amongst the rarest mosses in Poland and all are fully protected by law (Official Gazette Announcing Current Legislation, item 1409, 2014). Almost all, except Z. stirtonii which was reported in 2007 (Stebel et al. in Blockeel et al.,2007), have been placed on the ‘Red-list of mosses in Poland’ and classified as Endangered (Żarnowiec et al.,2004). Results of the present investigation allow amore precise analysis of the threats of these species (Table 1). Zygodon gracilis and Z. stirtonii occurring only at single localities and forming scanty populations are both of ahigh category (Critically Endangered). They are threatened by both natural (e.g., storm, fire) and anthropogenic (intensive tourism, air pollution, plant collection) factors. Zygodon gracilis is also classified as Vulnerable in Europe (Schumacker &Martiny,1995). Zygodon dentatus, Z. gracilis and Z. stirtonii are on the candidate list for the new Red-list of threatened European bryophytes (Hodgetts, 2015). 246 A. Stebel &J.Żarnowiec

Table 1. Species richness of Zygodon in Poland and neighbouring countries and state of their threat

Species forsteri gracilis stirtonii dentatus rupestris Country conoideus viridissimus Z. Z. Z. Z. Z. Z. Z. Poland · VU · CR NT CR EN Germany 1 ++0R+VV Czech Republic 2 · LR-nt ··LR-nt · EN Slovakia 3 · CR · CR CR ··8 Ukraine 4 · + ··+·+ Belarus 5 ······· Lithuania 6 ····3·+ Russia 7 (Kaliningrad Province) ·······

Key: 1 – follows Meinunger &Schröder (2007) and www.moose-deutschland.de; 2 – follows Vondráček (1994) and Kučera et al. (2012); 3 – follows Vondráček (1994), Kubinská et al. (2001) and Plášek (2007); 4 – follows Virchenko (2005) and Ignatov et al. (2006); 5 – follows Rykovsky &Maslovsky (2004) and Ignatov et al. (2006); 6 – follows Jukoniene (1996, 2002, 2003) and Ignatov et al. (2006); 7 – follows Ignatov et al. (2006); 8 – Kubinská et al. (2001) cited Z. viridissimus (with CR category) on the base specimen collected by Bauer in 1923 but the material is Z. rupestris (Plášek, 2007). + – species occurring but is not threatened; · – species not occurring. Threat categories: IUCN categories – CR (Critically Endangered), EN (Endangered), VU (Vulnerable), NT (Near Threatened); specificcountry categories – Czech Republic – LR-nt (Lower Risk-Near Threatened), Germany – 0(Regionally Extinct), R(Extremely Rare), V(Near Threatened), Lithuania – 3(Vulnerable).

The distribution maps of particular species of the genus Zygodon in Poland clearly refer to their distribution in the neighboring countries, for example in Germany (Meinunger &Schröder,2007), Czech Republic and Slovakia (Vondráček, 1994; Plášek, 2007; Marková &Plášek, 2012). There are three evident distribution patterns of these species: (i)distribution limited to the mountain areas (mainly the Carpathians) in southern Poland (Z. dentatus and Z. gracilis), (ii)distribution limited to north-western Poland, areas with the humid climate, influenced by the Baltic Sea and the Atlantic (Z. stirtonii and Z. viridissimus), (iii)distribution dispersed in the whole of Poland, with aclearl density of stations in the Carpathians (Z. rupestris) (Figs 38-42). In its only stations in Poland Zygodon gracilis,together with other calcicolous bryophytes and lichens, form epilithic communities from the order Ctenidietalia mollusci Hadač & Šmarda 1944, intermixed with patches of communities from the class Asplenietea rupestria Br-Bl 1926, compatible with its ecological amplitude and phytocoenotical preferences (Marstaller,1993; Dierßen, 2001; Müller,2005). The remaining species grow mainly as epiphytes (altogether 92.7% of records), rarely on bark of decaying logs (3.7% of records) and sporadically on concrete constructions (1.2% of records) or on outcrop of sandstone (1.2% of records). In other regions of Europe these species more often occur on stone and brick walls and concrete (e.g., Vo ndráček, 1994; Smith, 2004; Calabrese & Muñoz, 2008). The mosses have been noted on 11 species of host-trees, including 10 broad- leaved trees and one coniferous tree. Most frequently they overgrew bark of Fagus sylvatica (in total 64.6% of records), rarely Quercus robur and Q. petraea (7.6% of Zygodon in Poland 247 records), Salix alba and S. fragilis (8.9% of records), Fraxinus excelsior (5.1% of records) and sporadically on others (1.3%-2.5% of records). Probably in recent decades the oaks have played agreater role as host-trees for Zygodon species, as shown by an analysis of old herbarium collections. Koperski (1998) showed that the slightly acidic bark of oaks influenced by acid rain does not favour the occurrence of neutrophilic and slightly basiphilic bryophytes, including Zygodon spp. Beeches, the bark of which is slightly basiphilic and in old individuals has astructure similar to oak’sbark (Packham et al.,2012), in areas of high air pollution took over the role of the principal host trees for epiphytic bryophytes (Koperski, 1998). Recent investigations shows that among forest trees an exceptionally rich epiphytic bryophyte flora occurs on the bark of beeches (e.g. Mickiewicz, 1965; Bates et al., 2004; Packham et al.,2012). In Poland Zygodon species occurring in epiphytic communities from the class Neckeretea complanatae Marst. 1986 and Frullanio dilatatae-Leucodontetea sciuroidis Mohan 1978 em.Marst. 1985 and their phytosociological preferences coincide with those observed in Western Europe (Marstaller,1993; Dierßen, 2001). They grow as epiphytes mainly in forests (altogether 85.1% of records), rarely on wayside and solitary trees (14.9% records). Their optimum occurrence is in rich deciduous forests of the class Querco-Fagetea Br.-Bl. et Vlieg. 1937 mainly in neutrophilous beech associations of the order Fagetaliasylvaticae Pawł. apud Pawł. et al. 1928 (74.3% of records). They rarely grow in willow and poplar riparian forest of the order Populetalia albae Br.-Bl. ex Tchou 1948. Zygodon dentatus and Z. rupestris were included into agroup of primeval forest species as indicators of the best preserved patches of Carpathian beechwood (Stebel & Żarnowiec, 2014). As an effect of the anthropogenic changes in the environment, such as fragmentation of forest complexes, air pollution and long-term influence of acid rain, for example in the Beskidy Zachodnie Mts (Western Carpathians, southern Poland), Zygodon dentatus and Z. rupestris lost in the recent decades about 80% of their stations (Stebel, 2006). At present, small populations of Z. dentatus and Z. rupestris are in expansion, sometimes occurring even on wayside and solitary trees in villages. It seems that, together with decreasing air pollution, frequency of occurrence of these species increases. Similar data are reported from other countries, and Marková &Plášek (2012) suggest, that Z. dentatus is starting to spread in the south-western part of the Czech Republic and van der Pluijm (2012) reported, that in the Netherlands Z. conoideus and Z. viridissimus rapidly spread. Acknowledgements. Thanks are due to two anonymous reviewers for valuable comments which helped to improve the manuscript. We are grateful to the curators at KRAM, LBL, OSTR, POZG, WA and WRSL for kindly allowing us to study herbarium specimens of the genus Zygodon and to Professor Rod D. Seppelt, Bundall, Queensland, Australia for improving the English.

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