Resumen
This study of populations of Cypripedium calceolus L., Cypripedium macranthon Sw. and their hybrid Cypripedium ventricosum Sw. in several regions of Siberia was carried out in 2009?2014. Isolated and mixed populations of the two species and their hybrid were surveyed. In sympatric populations, C. macranthon is most common in the central part and those of C. calceolus prevail in the western part of the range. Mature vegetative and/or reproductive shoots were present but vegetative reproduction was clearly most important in most of the populations investigated. Five colour variations were recorded for C. ventricosum. All species benefit from the increase in the intensity of light reaching ground level in forests after ground fires in spring destroy young trees and undergrowth. Vegetative reproduction and the size of the plants increases in burnt areas. Important factors determining the size and the ontogenetic structure of Cypripedium populations are: the duration of the growing season, the ecological conditions, the activities of pollinators and the relationships among the three species in sympatric populations.