The article presents results of research on land ecosystems, in particular forest, xerothermic and sinanthropic ecosystems, as well as on the flora of West Polesie, mainly in its Polish and Ukrainian parts. The article includes a synthetic compilation of data on forest, xerotermic and sinanthropic ecosystems and less common flora of vascular plants of West Polesie. The problems of the restitution and reintroduction of very rare, endangered plants and phytocenoses as well as the problem of conservation have been considered. West Polesie is an area of a diversified floral cover. In the area analysed in this study, a total of 320 plant associations and plant communities of a debatable membership in the associations have been recorded 70 associations have been charactrised as rare. The flora of the vascular plants of West Polesie includes ea. 1500 species. Out of which 116 species receive (strict or partial) legal protection in the territory of Poland, 36 receive regional protection in Ukraine, and 170 are counted among locally rare or very rare. Thirteen species have been CORINE-listed, 23 species have been listed in the Polish Red Book of Plants and 48 species in the Ukrainian Red Book of Plants.