The purpose of this study is to make an inventory of the relicts in the flora of Lozenska Mt., to clarify their origin, taxonomical, ecological and phytogeographical structure and to evaluate their role for the formation of the contemporary flora and vegetation, economic uses and measures for their con- servation. The study was conducted in the period 2017-2019. In order to cover the maximum area and different ecological niches, the sampling was conducted using the transect method. The surveyed territory and its two geographic regions, north-west and south-east, were divided into four sub re- gions (parts) and 19 transects were used for possible comparisons. The biology and ecology of the relict plants was made, thus allowing to group the species in biological and ecological groups, based on life forms, floristic and phytogeographical elements, synanthropy and economic uses. As a result, 61 species and three subspecies, belonging to 48 genera and 35 families, were identified as relict taxa. These number represent 7.4% of the whole flora of Lozenska Mt. (823 species) and 17.6% of the relict species in Bulgarian flora. Tertiary were 93.4% of the mountain’s relicts. The families with the richest number of relict species were Salicaceae (9 species) and Ranunculaceae (4 species). The genera with the largest number of relict species were Salix (5 species) and Populus (4 species). The most relicts (73.7% from their total number on the territory of the mountain) were registered in the south-west part of the mountain, while the smallest number (52.5%) was found in its north-east and south-east parts. The phanerophytes (dominated by the threes) prevailed with more than 60%, followed by the hemicryptophytes (16.4%) and geophytes (13.1%). Most of the relicts on the territory of the Lozenska Mt. have Euroasiatic (17.7%) and sub-Mediterranean (17.7%) origin. The established relicts are pre- dominantly heliophytes (61.3%), mesotherms (86.9%) and mesophytes (59.0%). Each of the studied species is a plant with economic benefits: forestry (36.1%), non-wood resources (88.5%) or ornamental uses (54.1%). Salix caprea and Polygonatum odoratum are included in the Bulgarian Biodiversity Act (2002). The other relict species fall under provisions of different laws, such as the Medicinal plants Act, Forestry Act, Biodiversity Act, including NATuRA 2000 legislative base.
