Floristic and agronomic aspects of cereal weeds in the Constantine high plains.
Three hundred fifty nine fields of cereals were surveyed by stratified sampling in the Constantine high plains (north-east, Algeria). In total 254 species belonging to 34 plant families were recorded. The results indicated that five families the Asteraceae, Fabaceae, Poaceae, Brassicaceae and Apiaceae were prevalent and accounted for 55% of the species. Annuals (70%), broad leaved (87%) and the mediterranean floristic element (63%) were predominant and characterized the weed flora. The agronomic study permitted to distinguish 34 important species. This harmful flora was characterized by the prevalence of annual and broad leaved weeds. Although number of grasses was low were some abundant and frequent e.g. Avena sterilis L. and Bromus rigidus Roth. Perennial species were represented by several weeds, the most frequent and abundant were Bunium incrassatum (Boiss.) B.T., Carduncellus pinnatus (Desf.) DC. and Convolvulus arvensis L.