A Móra Ferenc Múzeum Évkönyve, 1968. (Szeged, 1968)

Gallé, László: The xerothermic lichen species cladonia magyarica VAIN

in some seconds the gametes got activated, began swarming, then separated from one another explosionlike and swam away. Sometimes two-three gametes got on with sticking together, coming apart only later, in some distance from the mother cell. On the membrane of the mother cell emptied the site of the opening is obvious. In certain cases when the developing gametes can already be separated well without being pressed completely to one another for the time being, they begin to move already inside the mother cell. This movement lasts some seconds, sometimes however for some minutes, then the mother cell quickly opens and the exploding gametes are scattered with a fast swimming. Inside the empty cell wall some gametes are sometimes left behind. These are circulating in the empty mother cell for a long time - as long as a quarter or half an hour at last, losing their flagella , they become round. The gametes delivered are uniform, somewhat elongated, one of their ends being more pointed, the other one rounded off. Their size is 5-10X2-4 JU, they have on their pointed ends two flagella equally 6 fx long, with the help of which they are swimming with a lively, drilling motion being capable of a quick changing of direction. They often twirl round their own axis remaining in the same place and then, breaking off that motion, they are quickly swimming in a straight direction again. Sometimes they perform only the rotary motion described. The gametes swimming in straight direction may quickly come to a stop and begin turning round and round. That motion of theirs can last as long as 1-1 to 15-20 minutes. Their motion gets slower and slower, at last they cease to move, get rid of their flagella become round and, as independent cells, they begin to feed, grow, i. e. they begin to function as new cells. At the round end of gametes, a chromatophore can be found having either the shape of a trough tight on the wall or being stretched along the wall. The chromatophore sometimes fills in the whole body of gametes. In the gametes there cannot be demonstrated any nucleus or stigma, even by being stained. The isogametes may copulate in different ways. With their pointed and sometimes rounded ends or with their sides they adhere closely to each other, meanwhile turning round in the same place or advancing with a drilling motion. In some time their motion becomes slower, they flick more rarely with their flagellae, and finally they cease entirely to move. The physiological behaviour of the gonidium alga bred in the first series of culture was as follows. We have got the thalluses developed big from pure cultures in their most perfect form in DETMER's culture media of different concentrations. The colour of thalluses was a little lighter and their surface a little wetter, too, in the soil concoctions containing sugar. We have observed a development at an approximatley uniform pace in the soil concoctions containing glucose and in DETMER's culture media, The cultures were generally yellowish-green, granular, of a little surface with characteristic protrusions and dimples making wavy the surface of thalluses. In several cultures there developed not the original godinium of Cladonia magyarica but an epiphyte alga in symbiosis with the lichen thallus on its rugous surface. This fact, as an experimentary mistake, was already mentioned by R. CHODAT (1913, p. 193), as well. In the greatest part of cultures, however, there was reall the gonidium alga that was bred. In the second series of culture, made by the help of micro-manipulators, 244