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
complex adaptation. This latter extremist view is impractical also by affording few possibilities to trace the directions of the life-form adaptations of the species (MASSING, 1958). Beyond the considerations representing in general the leading principles of the life-form systems (cf. CAIN —CASTRO, 1959), RAUNKIAER'S main principles concerning the characteristics of life-forms are, summarily, as follows (1908): "The character must represent something fundamental in the plant's relationship to climate; it must be fairly easy to use, so that we may easily see in nature to which life-form a plant belongs; it must represent a single aspect of the plant (thus enabling a comparative statistical treatment of the vegetation of different regions)." Assimilating DARWIN'S evolutional concept, RAUNKIAER considered macroclimate and its changes, enacted in the course of geology and the evolution of the living world, the cause effecting the climatic adaptation of the plant species (cf. HANSEN, 1956). (RAUNKIAER discusses the adequate life-forms in harmony with the climatic zones characterized by KÖPPEN'S climatic diagrams). Although RAUNKIAER'S train of thought takes into account the difference of the absolute and relative ages of the given life-forms, his concept and practice failed to bring into full display the possibility of analogies, the assessment of the role and significance of the homologous life-forms in different times and in diverse climatic zones. It will be seen later that the problems arising in the evaluation of the climatic role of the several life-forms derive partly from this failure. II. Definition and problematics of the life-forms Accepting RAUNKIAER'S basic conception, life-form, in the formulation of the present authors, is a characteristic of vascular plants which expresses the rate and quality of adaptation to the unfavourable season. The quantitative adaptation to the unfavourable season manifests itself principally in the reversible reduction of the plant organs, whereas the qualitative adaptation presents itself in external and internal morphological features but in essence in the decrease (or temporary inactivity ) of the cnzym activity: in the suspension of the productional process. The correlation between the adaptation of the plant to the unfavourable season and its stature developed during the favourable one is strict and often causal (the extreme difference between the Therophyton and Phanerophyton should, for instance, be kept in mind). [At the same time, physiognomy ("habit", "Wuchsform", etc.) expresses already a "constitutional", e.g. taxonomic characteristic (cf. ScHMiTHÜSEN, 1961, and WARMING'S —unfortunately difficult — "Organisationsmerkmal — Anpassungsmerkmal" problem), and also some other (edaphic, special uptake, etc.) therefore non-climatic adaptations, so that a number of qualitative features of physiognomy (e.g. tuft trees, bottle trees) are generally not regarded as characteristics of the life-form.] On the other hand, the quantitative measurements (e.g. the height of the plant during the unfavourable season) are a life-form feature, because this expresses the recent end result of adaptation to macroclimate or rather to bioclimate, the differentiated layers of the microclimate. Among the morphological features, every morphologic arrangement produced for the sake of adaptation to the unfavourable climatic conditions is a life-form characteristic. From this point of view, a rather sharp difference should be made between the epigeous and hypogeous life-forms (more precisely: Phanerophyton versus the other four main types of life-forms). The Phanerophytes —as plants
