A detailed study of vascular plants in the Tobolinka Nature Reserve (Augustów Forest, NE Poland) was carried out in July 2016 and February 2020. The reserve covers a very small area, and the diversity of its plant communities is very low due to the high acidity of its habitats (extremely poor fen surrounding a small polyhumic lake; wet and mesic pine forest). Only 48 species were recorded, including five species red-listed nationally (e.g. Goodyera repens, Scheuchzeria palustris).