Remarks on the seasonal aspects of plant communities on cereal crop fields

Abstract

The present paper is a discussion on the external manifestations of periodicity in the appearance and various degrees of intensity of the developmental processes in communities of cereal fields. The result of these changes is a different appearance of the some community in the course of the annual developmental cycle. In the course of the vegetation season the particular species develop differently some flower in spring, the majority in summer and others as late as autumn. Observation of various associations with cereals indicates that some of them exhibit wide differences in the manifestation of development periodism. A larger or smaller number of stages and their shorter or longer duration may be observed. Floristically richer communities (large number of species represented by large number of individuals) show more pronounced developmental phases, whereas in poorer ones these phases are more uniformly distributed in the course of the vegetation season. Field communities developing in the poorest habitats exhibit fewer aspects, usually in summer. All Polish investigators agree as to the early spring, spring, early summer and late summer aspects. There are controversies concerning the autumn (stubblefield) aspect. The classification of stubble field phytocenoses as associations does not seem fully justified. This phytocenosis is a continuation of the development of the cereal including community under greatly changed light and microclimatic conditions. The floristic composition indicates a connection with a definite group of habitats, and thus, with communities of cereal crops.