Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 66. (Budapest 1974)
Hajdu, L.: Filamentous Algae in Városligeti-tó, Budapest
58 L. HAJDÚ relatively fast. (The water of the pond oozed away into the ground due to an artifical groundwater drainage in September. Under a 10 cm water layer a Spirogyra mat of 5m 2 size was found where the process in 80 per cent of the cases reached the stage of spore formation. From this mat we have abundant sample both dried and formalin conserved one. At the time of spore formation there were numerous epithytes on the Spirogyra threads (PANKOW 1961). The algal mat of the pond was very uniform. Spots oi Ohara vulgaris L. and Najas minor were only occasionally found. Ceratophyllum demersum was relatively numerous. In August the algal mat becomes gradually separated from the bottom and is drifted to and from on the water surface. This in our case was due to the circumstance that the oxygen bubles produced by way of assimilation passed easily through the coarse-textured, loose Cladophora mat yet some of them got captured •among the small Hydrodictyon-nets below and among the Cladophores passing upwards the little balloon rearranges the threads of the mat : from the bottom an empty, gradually growing, Cladophora-walled cone passes upwards with Hydrodictyon at its top. Reaching the surface the top of the cone opens and later on becomes •completely detached from the bottom as a consequence of the smallest wavemotion. References HORTOBÁGYI, T.: Catalogus et Iconographia Algarum Hungáriáé in Institutum Bot. Univ. Agr. Gödöllő (status Nov. 1973, Manuscript). KADLUBOWSKA, J. Z. (1972): Zygnemaceae in Flora Slodkovodna Polski PWN Krakow. p. 1-431. KOL, E. (1956) : Comparative algological and hydrobiological studies in rice fields in Hungary - Acta Bot. Hung., 2: 309-363. BANGER, S. (1934): Monographische Bearbeitung der Spirogyren mit besonderer Berücksichtigung der Vorkriesungarisehen Verhältnisse — Folia Cryptogamica, 1: 1253 — 1306. MROZINSKA - WEBB, T. (1969) : Oedogoniales in Flora Slodkovodna Polski- PWN Krakow, p. 1-659. PANKOW, H. (1961): Über die Ursachen des Fehlens von Epiphyten auf Zygnemalen. — Arch. Protistenk., 105: 417-444. ISOKAL, R. R. & SNEATH, P. II. A. (1963): Principles of Numerical Taxonomy. - Freeman and Co., San Francisco — London, p. 1 — 359. •SÖRENSEN, I. (1950): Studies in the Ecology of Hydrodictyon reticulatum (L.) Lagerh. - Oikos, 2: 197-212. SVÁB, J. (1967): Biometriai módszerek a mezőgazdasági kutatásban — Mezőgazd. Kiadó, Budapest, p. 1 —498. VAN DEN HOEK, C. (1963) : Revision of the European species of Cladophora — Leiden, E. J. Brill, p. 1-248. Author's address: Dr. L. HAJDU Botanical Department of the Hungarian Natural History Museum H — 1146 Budapest, Vajdahunyadvár Hungary
