Pollen morphology and variability of invasive Spiraea tomentosa L. (Rosaceae) from populations in Poland

The aim of this study was to investigate the pollen morphology and the ranges of intraspecific and interindividual variability of the North American steeplebush—Spiraea tomentosa L., an invasive species in Poland. Steeplebush inflorescences were collected randomly from 30 localities of S. tomentosa in Poland. In total, 900 pollen grains were analysed with both a light and a scanning electron microscope. Nine quantitative and three qualitative...