Studies were carried out of three populations of Listera ovata from Siedlce environs (Siedlecka Upland). Two of them were situated at anthropogenic (Mościbrody and Rybakówka) and one at natural (Kisielany) stations. Biometric measurements of individual and group features were realized between 1996 and 1999. Aboundance of the studied populations of Listera ovata is much higher in comparison with aboundance of other populations in the scale of the country. Most aboundant populations were observed on antropogenic stations. However human activity also does not significantly affect the features of particular specimens.

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