Studia bot. hung. 44, pp. 5–192, 2013 THE GENUS BRYUM (BRYACEAE, MUSCI) IN HUNGARY P. Erzberger1 and W. Schröder2 1Belziger Str. 37, D–10823 Berlin, Germany; [email protected] 2Ludwigsstädter Str. 51, D–96337 Ludwigsstadt, Germany; [email protected] All available specimens of Bryum collected in Hungary in Hungarian herbaria (BP, EGR) and collec- tions of the fi rst author (B), altogether more than 2,100 specimens, were revised. Th e following thirty- four taxa were found to occur in Hungary: Bryum algovicum, B. alpinum, B. archangelicum, B. argen- teum, B. bimum, B. caespiticium, B. capillare, B. creberrimum, B. dichotomum, B. ele gans, B. funckii, B. gemmiferum, B. gemmilucens, B. intermedium, B. klinggraeffi i, B. kunzei, B. lon chocaulon, B. mildeanum, B. moravicum, B. neodamense, B. pallens, B. pallescens, B. pseudo tri quet rum, B. radiculosum, B. rubens, B. ruderale, B. stirtonii, B. subapiculatum, B. tor ques cens, B. tur binatum, B. uliginosum, B. violaceum, B. warneum, and B. weigelii. Th ree more taxa, i.e. B. ba di um, B. knowltonii, and B. tenuisetum, are also pos- sibly members of the Hungarian bryo fl ora, but the material was insuffi cient in some way or other to sup- port full verifi cation of their presence. Th e following species are excluded: B. bar nesii, B. born holmense, B. cyclophyllum, B. schlei cheri, B. veronense, and B. versicolor. A key, detailed descriptions, illustrations, and distribution maps are provided, with notes on habitat, associated bryophytes, and red list status. Key words: associated bryophytes, distribution maps, habitat requirements, illustrated key, mor- phological descriptions, mosses, redlisted species INTRODUCTION Recent checklists addressed the seemingly simple question: Which species form part of the Hungarian bryophyte fl ora? (Erzberger and Papp 2004, Papp et al. 2010). Th e latter also evaluated the threat status of many species in the form of a red list, and was updated with some recently discovered species. However, both checklists remain provisional with respect to some diffi cult groups where revisionary work had not yet been completed, in spite of substantial progress in the family of Grimmiaceae (Erzberger 2009, Erzberger and Schröder 2008). Bryum, a genus of well-known complexity, is one of the groups of species hitherto not covered by a thorough revision, and the present work attempts to fi ll this gap in the understanding of the Hungarian bryofl ora. Boros and Vajda, the two outstanding Hungarian bryologists of the 20th century, did not them- selves master this diffi cult genus, but relied on specimens determined or revised by the Bryum specialist Podpera, as research in the bryophyte collections of the Hungarian Natural History Museum in Budapest (BP) and of the Eszterházy Károly College in Eger (EGR) revealed. Since Podpera’s time, there have been Studia botanica hungarica 44, 2013 Hungarian Natural History Museum, Budapest 6 ERZBERGER, P. and SCHRÖDER, W. substantial changes in many aspects of taxonomy and nomenclature. Hundreds of infraspecifi c taxa described by Podpera (1957, 1973) are no longer thought to be of taxonomic relevance, but simply illustrate the variability of species. Holyoak (2003, 2004) has made some very relevant contributions, especially by merging taxa hitherto distinguished with great eff ort and not always success- fully: B. imbricatum, B. inclinatum, B. stenotrichum, B. amblyodon, and B. archan- gelicum are now united under the latter name, and B. rutilans, B. oeneum and B. subelegans have been included in B. pallens. B. mamillatum is thought to be a form of B. warneum; several taxa related to B. bicolor, e.g. B. barnesii, are in- cluded in B. dichotomum, and B. stirtonii in B. elegans. B. versicolor and B. dunense are also included in B. dichotomum (Holyoak 2003), but according to recent DNA studies, at least part of “B. dunense” may represent a taxon distinct from “B. bicolor” (Lockhart et al. 2012: 530). B. neodamense is considered a mere form of B. pseudotriquetrum (Holyoak and Hedenäs 2006). On the other hand, some taxa have been upgraded to specifi c rank, e.g. B. caespiticium var. imbricatum is now considered a species, B. kunzei, by many authors (Guerra et al. 2010, Hallingbäck 2008, Holyoak 2004). In some groups of particularly diffi cult taxa, e.g. the B. pallescens group, new approaches have been put forward (Zolotov 2000, Meinunger and Schröder 2007), focussing on the polyoi- cous B. lonchocaulon. When revising genera of Grimmiaceae, it turned out that many of the choro- logical data in the standard treatments of the Hungarian bryofl ora (Boros 1953, 1968), Orbán and Vajda (1983) had to be amended to a larger or lesser degree, because some were based on misidentifi ed specimens. Th ese specimens can oft en be located, thus allowing erroneous conclusions to be corrected, only because the bryological collections in Hungarian herbaria (BP, EGR) are nearly complete. We presumed that in the large and diffi cult genus Bryum substantial corrections are overdue more than half a century aft er the original determinations. Th e following questions are addressed in the present study: Which species of Bryum occur in Hungary? What is their distribution within the country? What conclusions can be drawn by comparing the results with chorological data from the literature? In order to promote further fi eld research in Bryum, which seems necessary to gain up-to-date chorological data and an improved basis for red list assess- ments, we tried to provide the most accurate descriptions possible with illustra- tions and a key for species determination. In addition to the species verifi ed for the Hungarian bryofl ora by our revision, some species that are at present not known from the Hungarian territory, but might be found there in the future, are included in our treatment of the genus. Studia bot. hung. 44, 2013 THE GENUS BRYUM (BRYACEAE, MUSCI) IN HUNGARY 7 MATERIAL AND METHODS All specimens labelled or inserted in Bryum (and collected in present-day Hungary) of the herbarium of the Natural History Museum, Budapest (BP), and the herbarium of the Eszterházy Károly College in Eger (EGR), altogether nearly 1,800 specimens, were revised by both authors, except for some specimens of B. argenteum, B. capillare, and B. moravicum, which were seen by the fi rst author only. In addition, the Hungarian collections (more than 350 specimens Bryum housed in the Botanical Museum Berlin-Dahlem – B) of the fi rst author were also revised. Th e total number of localised data complemented by evaluating mixed gatherings amounts to more than 2,600. Th ese include, however, numerous du- plicates. Not all specimens could be named, because the material was sometimes incomplete or otherwise unsuitable (about 200 specimens). In addition to specimens inserted in Bryum, some Hungarian specimens of Entosthodon longicolle (= Funaria hungarica) in the herbarium of the Royal Botanical Garden Edinburgh (E) and in BP were also examined, because they were reported to possibly contain additional material of the Bryum erythrocar- pum group (Crundwell and Nyholm 1964). Herbaria are abbreviated according to Index Herbariorum (Thiers 2008). Illustrations of individual species were prepared using a Leitz drawing ap- paratus. Distribution maps were prepared on the basis of the Central European mapping scheme (Niklfeld 1971), that has also been adopted by many recent Hungarian geobotanical works (e.g. Király 2003, Barina 2006). Open circles represent collections before 1973 (the year of Á. Boros’s death), closed circles aft er that year. In those cases where “old” and “recent” data were available for the same grid cell, only the recent data are shown in the map (i.e. “recent” over- writes “old”). Only specimens seen by the authors were evaluated for the maps. For some specimens the collection site could not be assigned unambiguously to a grid cell. Th ese data have been omitted in the maps. Since the genus Bryum is still controversial regarding its taxonomy and no- menclature, we decided to adopt pragmatic principles. We thus prefer binomials for taxa that are treated as infraspecifi c by many authors, for the simple reason, that subspecies and varieties, and even more so forms, have generally been and obviously will continue to be neglected by the majority of fi eld bryologists, as can be seen in many examples from the German bryofl ora (Meinunger and Schröder 2007). We do not want to claim that these taxa are in fact good spe- cies, and there may be sound reasons for not considering them so. However, since they are still controversial, it would, in our eyes, be the wrong decision to make them “disappear” behind other species. Th is treatment does not aim to refl ect ev- Studia bot. hung. 44, 2013 8 ERZBERGER, P. and SCHRÖDER, W. olutionary relations, but to provide a tool for further fi eld research, and to sum- marise the present state of knowledge on the distribution of Bryum in Hungary. Another pragmatic principle is to stick to traditional nomenclature versus the use of split genera (e.g. Holyoak and Pedersen 2007), thus avoiding many nomenclatural changes for which the basis, in our opinion, is still insuffi cient. For most taxa of Bryum, we follow the nomenclature of Hill et al. (2006), with the exceptions listed below (Table 1). Nomenclature of associating bryophytes mainly follows Papp et al. (2010), with some exceptions: Entosthodon longicolle (= E. hungaricus, Funaria hungarica) (Ros and Cano 2008), Syntrichia montana (= Tortula crinita), S. ruralis (= T. ruralis) (Gallego 2002), Tortula aestiva (= T. muralis var. aestiva) (Meinunger and Schröder 2007). Terminology used in the key and descriptions is based on Magill (1990). Table 1. Nomenclature of Bryum taxa in comparison to Hill et al. (2006). Accepted name Treatment in Hill et al.