The sex structure of entomogamic, dioecious creeping thistle population was the object of the research conducted during three years in the western part of Kampinoski National Park. It contains: sex-ratio of specimens (shoots), sex-ratio of flowers in inflorescences (capitula) and spatial structure of sex in populations. Field studies were conducted on 3 spatial scales. The number of capitula on particular shoots in each sex, height of shoots and number of flowers in capitula were investigated too.
The analysis of concentrations of shoots shows that patches with female shoots are dominant. There are also more patches with the cover of female specimens over 50%. Sex-ratio of female shoots to male shoots is 2.5:1. The male shoots produce more capitula (average 27.2) than female ones (average 17.3). Female shoots are slightly higher than male ones (respectively 86.4 cm and 83.6 cm). The results concerning the ratio of flowers in capitula are difficult for interpretation because on each plot the results were different.