Floristic aspects of weed flora of the oranian phytogeographic territory (North-West Algeria) and persistency of rare and/or endemic species. The weed flora of irrigated or dry (rain) crops as well as fallows of the Oranian area counts 425 species belonging to 51 botanical families and 217 genera. This flora was studied during two cropping seasons, respectively from January to July 2006 than from March to June 2009. Three families, the Asteraceae, Fabaceae and Poaceae accounted for 39 % of the species. Annuals (76%) and mediterranean floristic elements (57.64 %) were predominant and characterized the weed flora. Finally, the authors have proposed the modification of the distribution and the abundance of 17 species within the "Nouvelle Flore de l'Algérie" of Quézel & Santa (1962-1963).