Olea taxonomy is far from being clearly understood. Some molecular studies (Balboni et al. 2006, Besnard et al. 2009, Besnard et al. 2013) strongly suggest that there have been successive episodes of cross-breeding between feral and cultivated forms of Olea europaea, throughout the Mediterranean region for several centuries. As the cultivated forms were brought from the eastern to the western Mediterranean, they also crossbred with spontaneous Olea subspecies and then became feral. As centuries passed by, this process resulted in the gradual dilution of oriental haplotypes in to the western haplotypes.

However it is considered that some of the conclusions presented in the above molecular studies are not robust, since they may lack some taxonomic accuracy regarding the sampled taxa (with different taxa sampled as the same taxon) (J. Capelo pers. comm. 2016) and therefore molecular studies are not yet conclusive in terms of the taxonomy of this species; we follow the classical taxonomic treatment from Green (2002).

Four subspecies and one variety of Olea europaea L. are considered native to Europe (WCSP 2016):

• O. europaea subsp. cerasiformis G.Kunkel & Sunding
• O. europaea subsp. europaea
• O. europaea subsp. guanchica P.Vargas, J.Hess, Muñoz Garm. & Kadereit
• O. europaea var. sylvestris Brot.

These taxa are related to cultivated olive.

European regional assessment: Data Deficient (DD)
EU 28 regional assessment: Data Deficient (DD)

Olea europaea is regionally assessed as Data Deficient as there is currently insufficient information available on the European subpopulation size and distribution to make an informed decision. It is also not known to what extent the genetic identity of the wild subpopulations has been affected by hybridization with cultivated olive.

In the European region this species is native to southeastern and southwestern Europe and Macaronesia (Madeira and the Canary Islands). In Portugal, the species occurs in the northeast and centre-south of the country, while in Spain it is found all over the country. In France, it occurs in 18 departments to the south and southeast as well as Corsica (Association Tela Botanica 2000–2010). Its distribution extends outside Europe to western Asia (including Turkey), northern Africa, the western Indian Ocean, and the Arabian Peninsula (GRIN 2010).

The plants are scattered; often solitary. The European subpopulation is suspected to be decreasing.

It grows in secondary habitats, on dry slopes, and in maquis (in rocky areas), from 0–900 m.

The species is threatened by fires, secondary succession and by hybridization with cultivated olive.

The species is very widely cultivated and wild populations are important as potential gene donors for crop improvement. It is also collected from the wild for food and medicine.

EURISCO reports a large number of germplasm accessions of O. europaea held in European genebanks, however only one of which is reported to be of wild or weedy origin. This wild accession originates from Spain and is stored in the genebank of the Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Politécnica de Madrid, Spain (EURISCO Catalogue 2010). Germplasm collection and duplicated ex situ storage is a priority for this species.

It is recommended that the monitoring and management of this species is incorporated into the existing management plans of the protected areas in which it is found.

Research is needed to determine the effect of hybridization with cultivated olive on the genetic diversity of the wild subpopulations.