1 1Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Toppheideweg 88, 48161 Münster, Germany;, Email: firstname.lastname@example.org
Four Hirschmanniella species are known to occur in Europe: H. gracilis, H. loofi, H. behningi and H. zostericola; a fifth species, H. halophila sp. n., is described from Germany, where it was found along the Elbe estuary and on the adjoining coast of the North Sea. Three other species reported for Europe are considered as species inquirendae or appear to be misidentified. Based on sampling material from Germany, detailed morphological descriptions of H. gracilis, H. loofi and H. behningi are given; H. zostericola has not been found since its first description. The variability, even of characters of diagnostic significance, may be enormous, which makes correct identification difficult if little material is available. Hirschmanniella halophila sp. n. is morphologically very close to H. caudacrena, which has been isolated several times from aquarium plants imported from East Asia to Germany and for which morphological details are given. In Germany, H. gracilis is the most common species and is widely distributed; it is also known from many other European countries. Hirschmanniella loofi (also known from The Netherlands, Belgium, Poland and Italy) is less common. Hirschmanniella behningi, previously reported only from Russia and Sweden, was identified from nine places in Germany, including several coastal sites. Most of the Hirschmanniella records refer to moist soils with reed and other grasses or sedges; only H. gracilis was found exceptionally in arable soil. At many sampling sites, two or even three Hirschmanniella species co-occurred. A table for distinguishing the five European species is presented.