The area of Zelinska glava was declared a nature reserve on January 4, 1992. It is under the protection of a public institution Zeleni prsten Zagrebačke Županije and it covers an area of 9,5 km². Mountain meadows here alternate with deciduous forests, and there is also a significant amount of hazel shrubbery. Investigations of the area’s vascular flora first started during the 2019 growing season and continued in 2020. A total of 330 taxa of vascular flora were recorded, distributed among 82 plant families. 14 species of mosses were added to the list of vascular flora. The most common families are Compositae (13%), Fabaceae (7%), Rosaceae (7%) and Lamiaceae (6%). The analysis according to habitats shows that the largest number of taxa inhabits forest edges along paths (51%), followed by meadows (18%). Phytogeographic analysis shows that the highest representation of the Eurasian floristic element is 45%, followed by cultivated and adventive plants with 10,37%. Regarding life forms, the largest number of taxa belongs to hemicryptophytes (51%). According to the Red Book of Croatian vascular flora, 12 taxa were put in one of the endangered categories and eight taxa were protected by law, seven of which belong to the Orchidaceae family. A total of eight invasive species were recorded in the study area.