Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 62. (Budapest 1970)
Fekete, G. ; Szujkó-Lacza, J.: A survey of the plant life-form systems and the respective research approaches, II.
is why they are suitable for the analysis of community dynamics, and, in the case of comparisons, for an examination of related associations. SCHMID (1956, 1957) uses the Wuchsform criteria, worked out on the basis of his individual concepts, also for the description and comparison of associations. This concept rather approximates the growth form idea. His definition is as follows: "Als W T uchsformen werden hier die Formen bezeichnet, welche die ausgewachsene Individuen einer Art an Standort aufweisen. Das hat zur Folge, dass ein und dieselbe Species einer oder auch zwei oder sogar mehreren Wuchsformen angehören kann, je nachdem sie von Milieu mehr oder weniger begünstigt ist." In establishing his units, the chief criteria are the rate of lignification and the relationship of the persisting and seasonal (annually deciduous) shoots in the same plant. In his opinion, both criteria are the functions of climate. Further criteria are the height of the plant, the lenght of the internodes and the rate of ramification, as well as the relative duration and periodicity of the branches. As regards ramification, he emphasizes also the role of community structure, even for the same species. The root system of the plant and the character of the assimilatory organs also well characterize ecological conditions. By the combination of the above criteria, SCHMID establishes some Wuchsform-types. On the ground of his criteria, he attempts a simplified characterization of some significant phytoceonoses in the main vegetational zones of the northern hemisphere, e.g. a description and comparison of the Illyrian beech forests and the mixed woods (SCHMID, 1957). DANSEREAU (1951) and DANSEREAU & ARKOS (1959) apply their geometrical symbol system also for investigations in structure and dynamics, but these works will be discussed later. The works characterizing and analysing plant associations by RAUNKIAER'S life-forms will be treated also later. Some onto genetico-morphological approaches in life-form and growth form researches Of the Russian-Soviet zhiznennaya forma studies two approaches belong here : the comparative ontomorphogenetic and the experimental ontomorphogenetic approach. Comparative ontomorphogenetics investigates the ontomorphogenesis of the same or related species, either under different climates or in diverse coenological conditions. Extreme conditions are in this respect especially interesting, e.g. the areal confines of the species examined, wherein namely the necessary information can be obtained not only as regards ecological amplitude but also concerning the further evolutional direction of the life-form of the plant species. The founder of the Russian-Soviet life-form investigations is VUESOTZKY (1915) who established the first life-form system on the basis of the subterranean plant organs and the vegetative proliferating ability. WILLIAMS (1922) described the life-forms of meadow grasses. LAVRENKO (1936), founded his work on VUESOTZKY and KAZAKEVTCH'S* (1922) rhyzological studies in classifying the roottypes of psammophytons. PROZOROVSKI (1936, 1940) also elaborated a life-form system by the critérium of the rate of lignification. * On the Russian—Soviet classics see SZUJKÓ-LACZA & FEKETE, 1969.
