The Avendano Lagoon is located in the Province of Diguillin, Nuble Region, Chile and represents a very popular recreation area during the summer season. This note reports a floral list of the Lagoon Avendano and its environs, which differ in their levels of anthropization. We compared five sites by measuring composition and specific richness of the vegetation associated to them. The most altered sites, based on the number of introduced species, corresponded to open and recreational areas. Herein, 113 spontaneous species of vascular plants are documented, including 6 Pteridophyta, 77 Dicotyledoneae, and 30 Monocotyledoneae. From these, 13.3% are endemic, 52.2 native, and 34.5% alien species. The most frequently represented families were Poaceae, Asteraceae, Cyperaceae and Scrophulariaceae. The purpose of this catalog was to describe the flora of vascular plant surrounding the body of water of this lagoon which has a large tourist importance for the Commune of Quillon, linking the plant composition with the land uses in its borders.