Notes on the habitat and distribution of Avena species in the Mediterranean and Middle East

Abstract

Brief descriptions of the habitats and distributions of Avena species in the Mediterranean and Near East areas are given. These are based on observations made by the authors in three expeditions undertaken during the last decade.Avena pilosa, at its highest distributional density, is a primary component of the Quercus brantii climax area. The main concentration of A. clauda is in the Pistacia–Amygdalus steppe forest which is usually adjacent to the former species. Avena clauda is also a weed in some places in Iran. Both A. pilosa and A. clauda form large populations in Turkish and Iraqui Kurdistan and Iran but small and scattered populations in the Mediterranean region. Avena ventricosa is a rare and scattered species; it is probably of a relic nature and is found only in undisturbed habitats. Avena longiglumis is primarily a Mediterranean species and prefers light or sandy soil. The aggregate A. hirtula–wiestii is Arabo–Nubian–Mediterranean, and forms dense colonies. Avena barbata is Mediterranean – West Irano – Turanian and it is a common weed in all of the Mediterranean area. Avena sterilis is the most common species, and is also the most aggressive weed among oat species from Afghanistan to the Atlantic coast. Avena sterilis is a component of many East Mediterranean – West Irano – Turanian associations with oaks, or shrubs such as Poterietum spinosum. Avena fatua is rare in the areas explored by the authors, but it did occur as a weed of cultivation in areas under strong steppical or continental conditions, such as in northwestern Iran or eastern Turkey. Avena sativa–byzantina aggr. is a weed of cereals in the Mediterranean area, and it is grown as a cereal in northwestern Turkey and northwestern Iran.