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

Stollmayerné Boncz, Emilia: The alga species of the Csömör pool II.

Other values above the average include those of April 1990 (10.75 species/sample) and April 1988, October 1987 and November 1989 (10 species/sample). In the samples collected in April, besides considerable number of Chlorophytons there were numerous representatives of Xanthophyceae and Bacillariophyceae as well as samples collected from the benthos. In the two samples collected in October we find very high number of Bacillariophyceae. The values of the samples June 1988 and May 1990 can be considered as relatively high (9.33 and 9.25 species/sample, respectively). In June, this fairly high value resulted from the relative abundance of several taxa and a XanthophyaceaeChlorophyton dominance (immersed and benthic samples). It is striking that compared to the algal peaks of June in 1984 and 1985, the highest values were found in July and August in the period 1987-1990 (Fig. 1). In the study period 1984-85, only immersed samples were taken; therefore immersed samples were selected for comparison from the period 1987-1990 as well, with Euglenophyta and Pyrrophyta species extracted. The resulting values of 1987-1990 were compared to them as well (Fig. 3, Table 2). It seemed reasonable to study the seasonality of the individual algal groups (Fig. 2). On the basis of this, a Cyanophyton peak was observed in July 1988 (3.25), it was relatively high in September and November 1987. This taxon was not observed in October 1987 and very few in March 1990 (0.20), May 1990 and November 1989 (0.50). An Euglenophyton peak was observed in August 1988 (1.5), as well as in September 1987 and 1988 (1.0). The taxon was completely missing in April and June, as well as October 1987. A Xanthophyceae peak was demonstrated in May 1990 (2.25) and April 1988 (2). The species was absent in March 1988 but relatively high in 1990 (1.66). It was missing in August, which is not a great surprise because only sampling points 2 and 6, otherwise poor in Xanthophyceae species, were available (Table 3). Pyrrhophyta species occurred in May and June only. A Bacillariophyceae peak was observed in October 1987 (8), the taxon was relatively frequent in August and November 1989 (6.5). The minimum was observed in May 1988 (0.33). A Chlorophyton peak was found in October 1988 (5.66), they were fairly frequent in April and July (4.25). The taxon was absent in March 1988. It seems that the biotops of the Csömör pool can be characterised by a definite dominance of Bacillariophyceae and a less marked dominance of Chlorophytons. Pattern The number of the individual sampling points changed from year to year and month to month. For the sake of comparison, the values in the Table (Table 3) already represent the number of species per sample (species/test). As the individual sampling points could be used for different times, as a background of information, the number of sampling is marked at each point. Thus the relative