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

Gallé, László: The xerothermic lichen species cladonia magyarica VAIN

paraphyses being close to one another, and the coloured, somewhat knobby hypha-ends of paraphyses are forming a real light-shade ensuring a defence against the scorching sunlight, as well. The gonidia-algae themselves are not too sensitive organisms, either. That is shown by the fact that the algae survive in the arctic region on the surface of snow similarly as in the thermal waters. Our lichen finds the optimal contitions necessary for ite development in the wetter and periods of Spring and Autumn, resp. in a less warm early Summer. In the spring months (April-May), in four weecks, the young podetia developing from the thallus are achieving a size of 2—3 mm. During the great aridity there don't appear any new young podetia. Then the lichen does not grow, either. The optimum of growth falls, therefore, on the spring months. In the summer months, because of the insolation, the high temperature, the withering caused by the great loss of water and, last but not least, as a consequence of the aeolian, moreover the zoogene and anthropogene effects, the lichen is sufferring much and in the woods visited strongly in the Great Hungarian Plain there are scarcely to be found any healthy substances and healthy thalluses. Concerning the water preservation, Cladonia magyarica is, anyhow, making use also of the capacity of water preservation of moss plants occurring together with it (Syntrichia ruralis var. arenicola, Pleurochaete squarrosa, Ceratodon purpureus, etc.). Together with the mosses, the leaves falling on the soil surface, the stem formulae, the thallus is forming a left-like texture that, like a sponge, is resorbing in itself vapour, dew and other preeeipitation of liquid state. Owing to that, in wet, foggy weather, in dewy mornings, the lichen thalluses become soft; after sunset, however, they grow dry, become fragile. As mentioned above, the lichen thalluses are often tread underfoot, diddled out of their accustomed site, knocked down by pasturing animals and people working in the forest. In that case the podetia that are normally in a vertical site are getting on the surface of sand into a horizontal position and often even upside down. In the thallus has still enough water reserve or if it becomes wet so the podetia begin to proliferate. There appear on them not only new secondary squamae but also small secondary and tertiary funnels growing upwards (Cf. Table I. Fig. 8., 9., and Cf. PISŰT 1961:371, Fig. d.) It was interesting to observere how Cladonia magyarica is defending itself against wind and against being covered by the quicksand. The wind often fills in the depressions occupied by Cladoniae with sand, decaying leaves, vegetable debris. First the primary thallus is getting under sand then often even the podetia themselwes. At any rate, as soon as a buried thallus like that can get some moisture, there grow upwards new thallus squamae at the end of podetia, there are sprouting new, young podetia. In that way the plant is striving to get over the sand. If, however, it cannot get any precipitation in due time then the lichen thalluses perish. If, on the other hand, it can get some precipitation and a regeneration occurs then only the thallus pieces and podetia are decaying that have remained under the surface of sand. They increase in both cases the humus content of the sand soil. The regenerating podetia like these can, however, be befallen by a further disaster, as well. In that case the regenerating processe is anew beginning, and fantastic shapes may be produced. 250