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

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

evident that the Sphagnum species could not possibly survive this shock. Fern species started to regenerate to some extent, otherwise vegetation life practically ceased on the island. The vegetation of the pool started to regenerate slowly, with theexception of the island, with Typha angustifolia spreading heavily. The fire had terminated several mosses and flowering-plant species. As autumn came, the 'island' could be neared on foot. Spreading of Lastrea thefypteris and masses of Ambtystegium riparium was plainly visible. In some parts and certain periods, the moss species Ricciocarpus natans and Lemna trisulca became more frequent on the water surface. The changes were quite appealing. The pH value rose to 7. This change in itself necessitated new algological investigations. The sampling procedure was started in September, 1987 and continued during 1988. Water samples were taken in November 1989 and March, April, May of 1990 as well. The value of pH was uniformly 6-7. In most places and times, it was about 6, otherwise around 6.5 or 7 (average value pH 6,5). This shows one degree of raise compared to 1984-85. The measurements of pH indicate that the slightly acidic marshy waters have shifted towards neutral water chemistry. Map 1. Map of Csömör pool 1= Csömör pool, 2= Csömör village, 3= Csömör brook, 4= 16th district of Budapest, 5= suburban railway terminal, 6= suburban railway, 7= forest Section of the Budapest 1971-601-949/IV map from Cartographia. The pool was marked by B.E. Ákos Stollmayer.