B. Papp szerk.: Studia Botanica Hungarica 29. 1998 (Budapest, 1999)

Erzberger, Peter: Distribution of Dicranum viride and Dicranum tauricum in Hungary

in Central Europe D. tauricum occupies ecological niches that have been abandoned by other epiphytic moss species as a consequence of acid rain (FREY et al. 1995). Field observations of the author are not in agreement with this view. For example, on a single oak at Hárs-hegy (Budapest), D. tauricum was found growing together with Frullania dilatata, a liverwort of well-known and high sensitivity towards acid immissions, which, for this very reason, has already disappeared from a number of regions subject to sulphur dioxide pollution (e.g. DULL and MEINUNGER 1989, BENKERT et al. 1995). It seems, then, that in the surroundings of Budapest, at least, acid rain cannot be the effective cause. A different hypothesis assumes that D. tauricum favours increased nitrogen oxide concentrations due to traffic air pollution resulting in general eutrophication (BUTTERFASS 1992). Again, more detailed mapping could help to answer the question as to whether D. tauricum shows, in fact, preference for sites around human settlements and agglomerations. Studying transverse leaf sections of D. viride, the author noticed a morphological feature, which is also visible in Figure 2. The cell walls show projections, which are not observed in D. tauricum. In the literature, this character ("Pfeilerpapillen, papillenartige Auftreibungen über den Zellwänden") is described especially in Dicranum fulvum (LlMPRICHT 1889, ROTH 1903, BROTHERUS 1923, BURCK 1947), but also in Kiaeria falcata, K. blyttii (BURCK 1947, MAIER 1997) and Dicranoweisia crispula (MAIER and GEISSLER 1995). According to NYHOLM (1954, 1986) and the experience of the author, it is characteristic of section Crassinervia Roth of the genus Dicranum, comprising D. scottianum, D. fulvum and D. viride. However, HEGEWALD (1991A, b) also reports this feature ("Zellwände der Lamina stark verdickt mit warzenförmigen Ausbildungen") in leaves of D. fragilifolium and D. tauricum. The taxonomic value of this character obviously requires further study. * * * Acknowledgements. I wish to thank the directors and curators of the herbaria BP and EGR and the owners of private herbaria, G. Jakab (Szarvas), Z. Tóth and P. Szövényi (Budapest), for the loan of specimens, Gy. Szél for help with preparing the map, R. McF. Craig for correcting the English and J. Klawitter for helpful criticism of the manuscript. REFERENCES BENKERT, D., ERZBERGER, P., KLAWITTER, J., LINDER, W., LINKE, CH., SCHAEPE, A., STEINLAND, M. and WiEHLE, W. (1995): Liste der Moose von Brandenburg und Berlin mit Gefährdungsgiaden. - Verh. Bot. Ver. Berlin Brandenburg 128(1): 1-68.