B. Papp szerk.: Studia Botanica Hungarica 32. 2001 (Budapest, 2001)

Erzberger, Peter: Ditrichum crispatissimum (Muell. Hal.) Paris, a new species of the Hungarian bryoflora, and Ditrichum flexicaule (Schleich. ex Schwaegr.) Hampe in Hungary

caule is more drought-resistant (CASAS et al. 1990). This is in agreement with an Atlantic affinity in D. crispatissimum and a more continental character in D. flexicaule. But acceptance of Fris voll'

s concept is not unanimous. NOVOTNY (1997), using morphometrical and multivariate methods, claims the existence of transitional forms together with Frisvoll's taxa in former Czechoslovakia. Intermediate forms are also mentioned by SAUER (2000) for Southwest Germany. In Hungary, D. flexicaule s. 1. is frequent (BOROS 1968, ORBÁN and VAJDA 1983). Its distribution in Hungary and the surrounding Carpathian region has been compiled by ORBÁN (1974), but has not yet been treated taxonomically. For the preparation of an updated checklist of Hungarian bryophytes the following interrelated questions had to be answered: - Does D. crispatissimum occur in Hungary? - Can Frisvoll's concept successfully be applied to describe the variation within D. flexicaule s. 1. in Hungary, or is the resolution of the complex complicated in continental Europe by intermediates as suggested by NOVOTNY (1997)? As a contribution towards answering these questions, the specimens labelled D. flexicaule in BP collected in Hungary were revised. The results are presented in this paper. MATERIAL AND METHODS Nomenclature of mosses follows CORLEY etal. (1981) and CORLEY and CRUNDWELL (1991) in most cases, that of liverworts GROLLE and LONG (2000). Abbreviations of the herbariums: BP = Hungarian Natural History Museum, Budapest; B = Botanischer Garten und Botanisches Museum, Berlin-Dahlem. Taxonomic characters separating Ditrichum crispatissimum and D. flexicaule Initially, difficulties were encountered with the correct interpretation of some character states described in the literature for the differentiation between D. crispatissimum and D. flexicaule. Therefore, in addition to the 181 Hungarian specimens from BP some specimens from the author's herbarium and from B were studied. With the use of FRISVOLL (1985), among these additional specimens, six could be identified as D. crispatissimum. They originate from different parts of western and central Europe (Ireland, Scotland, France, Italy, Germany), and show the character states typical of this taxon. It turned out that some comments on the