Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 63. (Budapest 1971)

Fekete, G. ; Szujkó-Lacza, J.: A survey of the plant life-form systems and the respective research approaches III. Rankiaer's life-form conception. The application of life-forms in the characterization of phytoclimate and in vegetation analysis

in various continents of the World are

—despite their more or less great similarity in climate

—different. As in the former example, the cause lies in the diverse floral origins. For example, the prevailing life-forms of the given deserts display relationship not with one another but with the life-forms of the plants of those regions which surround the deserts. This fact also proves that some desert life-forms are comparatively young, the rate of transformation of their species is a function, beyond the genetical abilities of the species, of the age of evolvement and spreading velocity of the desert. The constant shifting of deserts causes a deep-reaching selection in the flora of the respective territory; the effects of the desert will appear pregnantly in the life-form of the surviving species. Presumably it is owing to this very effect that the extremely dry and hot desert climate is the least characterizable by RAUNKIAER'S life-form spectra. According to WALTER (1962), in the Egyptian

—Arabian deserts it is not the position of the renovating buds which expresses the adaptation to the heat and water climate held so important by RAUNKIAER. For this area therefore, ZOHARY (1952) elaborated water economy types for the basis of the biological spectra; ORSHAN, too, considered life-manner arrangements against drought the most important in survival (1953). Both authors subordinate RAUNKIAER'S criteria to those striking morphological modifications of the plant which evolve for the sake of reducing the transpiratory surface. For the overcoming of the unfavourable season, BATANOUNY

—BATANOUNY'S investigations (1968, 1969) also show that the type, vegetative ability, and depth of the root system, enabling water uptake from the soil

—moist only for some hours

— in the arid regions, are more important adaptive-survival factors than the lifeform (cf. ADAMSON, 1939). According to STANIUKOVICH (1949), the cold and dry climate of the Eastern Pamir resulted in similar stature and morphological adaptations in every life-form group. The Chamaephyton-climate is a much disputed problem. RAUNKIAER characterized successfully the arctic Chamaephyton-climate and separated it both latitudinally and altitudinally from the Hemicryptophyton-climate. On the other hand, HAGERUP (1930) demonstrated that it is a high Chamaephyton percentage which separates, e.g. in Timbuktu, the semi-desert from the desert. ADAMSON (1939) succeeded in recognizing that the cause of these two contradictory examples lies in the much too widely interpreted Chamaephytes (in the Arctis, mainly lignifying cushion plants and lignifying climbing Chamaephytes predominate; other, graminiform and lignifying erect forms in the dry climate). In all probability, the above mentioned arctic forms are life-form types selected by the ice ages; they well tolerate periglacial conditions even today. (Their survival and limits of distribution can be satisfactorily explained by the favourable microclimate

—as a limiting factor

—prevailing in June in the inclement macroclimatic space, and the intermediate position occupied between the protractedly frozen soil and the equally cold atmospheric cover). This does not preclude, however, that the abovementioned other types of the Chamaephytes evolve by definitely opposite climatic effects. If the various possibilities (which might equally be monophyletic and polyphyletic, both systematically and by life-forms) of the evolution of life-forms are taken into account, as well as the consideration that there are very many effects which may induce the evolvement of a life-form, it is easy to see that it may take a number of ways (ANDREÁNSZKY, 1954). CAIN (1950) formulated this problem as follows: "No life-form class is associated solely with a single environmental type." Collating the biological spectra of the deciduous and coniferous forest zones and climax grasslands (Hemicryptophyton-climate) of KÖPPEN'S C and D climates