B. Papp szerk.: Studia Botanica Hungarica 34. 2003 (Budapest, 2003)

Buczkó, Krisztina: Diadesmis brekkaensoides (W. Bock) Moser, Lange-Bertalot et Metzeltin: a new aerophytic diatom for the Hungarian flora

coming parallel at the poles, 30-35 per 10 pm. The frustules form band-like aggregations." BOCK (1963) did described details about the substrata where he found Navicula brekkaensoides: he only mentioned that it was found in the Alps on rock in a thin layer. KRAMMER and LANGE-BERTALOT (1985, 1986) later reduced this taxon to variety level under Navicula brekkaensis Petersen as Navicula brekkaensis var. brekkaensoides (W. Bock) Lange-Bertalot, but he did not provide a plausible argumentation for this taxonomic treatment. He did this in spite that BOCK (1963) had emphasised that Navicula brekkaensis cannot be found on limestone since it prefers non-calcareous substrates. This in fact, does not correspond with our sampling location, which is in limestone. Based on the substrate preferences lumping of these taxa seems quite unreasonable. Later Navicula brekkaensis var. brekkaensoides was transferred as a new species to the genus Diadesmis (MOSER et al. 1998). According to KUSBER and JAHN (2003) the valid name of this taxon is Diadesmis brekkaensoides (W. Bock) Moser, Lange-Bertalot et Metzeltin. Apart from the original description of the species (BOCK 1963) only one occurrence D. brekkaensoides had been known: MOSER et al. (1998) have reported it from New Caledonia. Web-sites with diatomological data and checklists Fig. 4. Diadesmis brekkaensoides

. Scale 10 u.m