L. Hably szerk.: Studia Botanica Hungarica 20. 1988 (Budapest, 1988)
Stollmayerné Boncz, Emilia: The alga species of the Csömör pool
STUDIA BOTANICA HUNGARICA (Antea: Fragmenta Botanica) XX. 1988 p. 63-75 The alga species of the Csömör pool By E. STOLLMAYER-BONCZ (Received October 30, 1987) Abstract: There is a peaty, marshy area near the village of Csömör, Pest county, surrounded by agricultural land which received protection in 1977. The higher plants of this pool have previously been reported by the author. In this publication a survey of the alga species found in the turbary pool is presented. Fifteen out of the 69 identified species are considered to be rare in Hungary. THE NATURAL GEOGRAPHICAL CONDITIONS OF THE CSÖMÖR POOL AND ITS SURROUNDINGS The small pool near Csömör is found in the left-hand side lateral valley of the stream Forrás, surrounded by agricultural land. It is marked by the OMMI genetic soil map as agriculturally untillable land. The pool cannot be found on maps, probably because of its small size. There is not much open water. In accordance with the weather and precipitation either the mobile sphagnum "island" in the middle of the pool is covered by water or, especially when drained, one can easily reach it in ankle boots on the moving moory surface. The studied pool is found in the northern Pest Plain part of the Dunamenti (Danube) Plain of varied relief, broken by alluvial aprons in the left-hand side lateral valley of the stream Forrás (alternatively known as Csömör) (Map 1). The stream Forrás is one of the third-rate left-hand side affluents of the Danube with extremely clear water. It runs into the stream Mogyoród which is-the right-hand side current of the,stream Szilas. The most important characteristics of the Pest Plain are as follows: Its area covers 700 km 2 , mean annual temperature is 10°C, annual precipitation is 600 mm, annual evaporation is 525 mm, annual outlet rate is 2. 5 1/sec/km 2 . The currents of the region are fed by springs seeping through the surface of Pliocene-Miocene strata on its eastern border (MAROSI and SZILÁRD 1967). The pH of the water of the pool was 5, 5 to 6.0, as determined by the generally used test paper on the spot. The valley surrounding the pool is placed on bed No. 3 of the Danube of the Middle Pleistocene, 34 m above the zero point of the Danube, north of the bed No. 4 without an overflow. The protected valley is covered by meadows, on boggy soils mainly with hayfields. Although the land on the northeastern and southwestern side of the pool is covered by sand and gravel, they are cultivated.
