L. Hably szerk.: Studia Botanica Hungarica 23. 1992 (Budapest, 1992)

Buczkó, Krisztina; Ács, Éva: Preliminary studies on the periphytic algae in the branch-system of the Danube at Cikolasziget (Hungary)

periphyton resembles at the periphyton of the flowing waters as well as that of the standing waters. As far as the richness of the taxa concerned these samples are reminiscent of lake periphyton. The great number of green algae also refer to the periphyton collected in lakes (ÁCS et al 1992,). The structure of the coats also shows differences between samples collected from standing and flowing waters. On the basis of our previous studies in lakes, we suppose that the typical lake periphyton consists of many tube dwelling diatoms (Cymbella species) and the Rhoicosphaenia, Gomphonema and Achnanthes species become fixed to the substrate with long stalks. These look like as a bucket. Achnanthes minutissima very often was the predominant taxon in the lake periphyton, and it was fixed with long stalk. On the contrary, in the summer period Achnanthes minutissima usually is not dominant in another part of the Danube (Göd section), where it occurs usually directly fixed onto the hosts without a stalk. In our samples from the Szigetköz Achnanthes Fig. 3. Dendrogram of the cluster analysis of 15 samples from, the branch-system of the Danube at Cikolasziget. Abbreviations: o=periphyton from old reed, g

=periphyton from green reed, R=periphyton from Rorippa amphibia stem, ?—periphyton from Polygonum amphibmm stem Ca

=periphyton from Carex acutiformis leaf, Bl=periphyton from twig before the flood, M

=periphyton from Myriophyllum verticillatum stem, B2=periphyton from twig after the flood 0,5