B. Papp szerk.: Studia Botanica Hungarica 30-31. 1999-2000 (Budapest, 2000)

Rákosi, László; Barbacka, Mária: Upper Cretaceous flora from Ajka (W Hungary). I. Thallophyta

ECOLOGICAL RELATIONS Found in between coal layers with marl, common among phytoplankton, Schizosporis reticulatus probably belongs to taxa living in freshwater. Similarly, green alga Munieria grambasti as well as Amblyochara begudiana and Mesochara symmetrica (Characeae) were found in these layers. These species occurred usually in the sublittoral zone of lakes. The order Lycopodiales is represented by Minerisporites (Isoëtaceae). They grew in humid soil conditions or under water, mainly in oligotrophic-dystrophic marsh-lakes. The species of the genus Minerisporites usually prefer coastal zones (either land or water). Lobasporites lobatus belongs to Marsileaceae, the members of which live in eutrophic, swampy, seasonally flooded areas or in freshwater puddles. Members of the family Salviniaceae prefer mainly warm climate in undisturbed, wind-protected, eutrophic fresh standing water. Species of the recent family Azollaceae are found mainly in tropical zones. Similarly to those of the family Salviniaceae, they grow in protected areas of standing water covering the water surface. PALAEOECOLOGICAL CONCLUSIONS In the Ajka Coal Formation the phytoplankton is represented by Schizosporis reticulatus (Zygnemataceae), and green alga by Munieria grambasti (Dasycladaceae), and the gyrogonites of Amblyochara begudiana, Mesochara symmetrica, Microchara laevigata (Characeae). All of these species require oxygen-rich, clear, oligotrophic, mainly freshwater and in certain cases oligohaline environment. In the case of the pteridophytes, representation of aquatic and terricolous plants, the megaspores and the massulae of the heterosporous species and large-scale occurrence of microspores of the homosporous types were identified. Systematically, the megaspores are represented by Lobasporites lobatus (Marsileaceae), Glomerisporites pupus (Salviniaceae), Azollopsis tometosa, A. pusilla (Azollaceae), Minesporites sp. (Isoëtaceae) and representative of Hydropteridales. The most characteristic microspores from the fossil community of the formation belong to the families Lycopodiaceae and Cyathaceae.