Factors determining the variability of the size of generative reproduction organs and leaves of Cytisus scoparius (L.) Link in western Poland

Common broom Cytisus scoparius (L.) Link is a native shrub, common both in Europe and Poland and in many other areas of the world, it is considered an invasive plant. e size of the organs of generative reproduction and the factors determining it are still poorly understood. The study of the size of broom flowers, fruits, seeds and leaves was carried out on 16 plots in western Poland. Habitats were described using Ellenberg’s index values, which allowed us to divide the study into two types: warm, rich in nitrogen, and moister with higher pH. It has been shown that a significant part of the variability in the size of flowers and their elements is conditioned by inter-individual differences. Some features (wings and keel area, number of seeds, or nitrogen content in stems) are also dependent on the type of habitat. Probably the key factor influencing the size of generative organs and the number of seeds is the availability of water in the environment. In more moist habitats and with a higher pH, the organs of generative reproduction are larger, and the nitrogen content is lower. The size of individual elements of the perianth is significantly correlated with each other, and the number of seeds depends on the size of the keel. Depending on environmental factors, the size of the generative organs may affect the efficiency of pollination, which in turn determines the size and number of seeds. The ability of C. scoparius to adapt to various edaphic conditions, the ability to establish symbiosis with atmospheric nitrogen-fixing bacteria, and the production of size-diverse flowers that can be pollinated by insects of various sizes determine its invasive success.