Contribution to the Knowledge of Bromus Diandrus–Rigidus (Poaceae) Polyploid Complex in the Bulgarian and Romanian Floras

Comparative morphological and ploidy level survey of the polyploid complex B. diandrus-rigidus in the Bulgarian and Romanian floras was performed. Critical examination of the morphology of the collected specimens revealed B. diandrus is represented in both floras. The species has already been reported for Romania under the name B. rigidus. For Bulgaria, the species has been very recently reported on a conference poster with a single gathering from 2020. Here, we provide more records of the species along the whole Bulgarian Black Sea coast floristic region, with the oldest gathering dating back to 2003. Ploidy level estimation of the Bulgarian accessions by flow cytometry revealed all studied populations are octoploid which is congruent with data from elsewhere, and confirms B. diandrus is present in the Bulgarian flora. For both the Bulgarian and Romanian floras alien status of the species has been inferred.