Thesium ebracteatum (Santalaceae) rediscovered in Romania: ecological and biogeographical context

Thesium ebracteatum Hayne is an endangered hemiparasitic plant, rare in the south-western part of its range. It is listed in Annex II of the EU Habitats Directive and appears on the national Red Lists of many European countries. In Romania, the species is considered extinct according to the national Red List, with only a few historical records from Transylvania.

In June 2025, approximately 100 individuals of T. ebracteatum were discovered near Bălcăuți, Suceava Region, Romania. This represents the first national record of the species in several decades and the first ever from eastern Romania. The species occurred in a stand documented by a vegetation plot, corresponding to the phytosociological association Brachypodio pinnati-Molinietum arundinaceae. The isolated occurrence near Bălcăuți, similar to other peripheral populations in the south-western part of the species' range, is regarded as relict. This interpretation is further supported by the disjunct occurrence of other rare plant species typical of peri-Carpathian forest-steppe. Historical maps indicate that the site once formed part of an extensive grassland complex known as Horaiț/Horaiza, most of which was converted to arable land during the 19^th and 20^th centuries. For the long-term conservation of T. ebracteatum and other rare species at the site, targeted management is required, including the prevention of further ploughing and the extension of legal protection to all valuable local stands.