B. Papp szerk.: Studia Botanica Hungarica 39. 2008 (Budapest, 2008)

Erzberger, P.; Schröder, W.: The genus Schistidium (Grimmiaceae, Musci) in Hungary

known at present, to be under-recorded. Although a first search along the banks of the Danube to find more S. platyphyllum was unsuccessful, it is hardly conceivable that there should be no more potential sites along this river in Hungary, considering the occurrence of this species along German lowland rivers. S. papillosum was discovered only recently at its only known growth site during a search of siliceous substrata for Schistidium. Although a few excursions were undertaken into such areas (in the Bükk and Börzsöny Mts), there remain many potentially rewarding places with siliceous bedrock in these mountains as well as in the Zemplén, Mátra, KarancsMedves, Börzsöny and Visegrád Mts to be explored in more detail. On the other hand, there are reasons to believe that S. confusum, with only one site, and in particular S. confertum and S. flaccidum, with two and three sites, respectively, might be truly rare. S. confusum and S. flaccidum are considered to be rare in Europe, and S. confertum is rare in Fennoscandia, but more widespread in Central and Southern Europe (BLOM 1996). In Hungary, S. confusum has been discovered only recently in a single population, in spite of plenty of potential growth sites on calcareous substrate throughout the country. The species circumscription of S. confertum and S. flaccidum has been stable within the last hundred years, and was known to Hungarian bryologists of former times. Their populations have been detected about fifty (S. confertum) and a hundred (S. flaccidum) years ago. No new site of either of them was found during fieldwork of the first author, but a single new location of S. flaccidum has been discovered recently (B. Papp, unpublished). The remaining taxa with only few records: S. pruinosum, S. dupretii, S. robustum, and S. brunnescens subsp. griseum are certainly not frequent, but may also be under-recorded, since there are two or three recently discovered sites for each of them. It is interesting to compare frequency and rarity of Hungarian taxa with data from other Central European countries, e.g. Austria (GRIMS 1999), Baden-Württemberg (HOLZ 2000) and Germany (MEINUNGER and SCHRODER 2007). As in Hungary, S. crassipilum and S. apocarpum are frequent and widely distributed in the above-named countries. Nearly as frequent is S. elegantulum in Baden-Württemberg, much less so in other parts of Germany, and in Austria. In Scandinavia, this species has a southwestern distribution (BLOM 1996), and perhaps some oceanic affinity is reflected in the