مار چمن

*Natrix natrix*, commonly known as the Grass Snake, Culebra de collar, Couleuvre à collier, užovka obojková, or Common Watersnake, is a species of reptile. It belongs to the family Colubridae within the order Squamata and the phylum Chordata. The species was described by Linnaeus in 1758 and is currently accepted as a valid taxon. Its IUCN conservation status is listed as Least Concern.

The organism inhabits freshwater environments and feeds primarily on amphibians. While its taxon range is noted as China, biological records and institutional collections from the United Kingdom, Russia, Hungary, and Romania also document its presence. The species is not extinct.