Abstract: A gear mechanism for agricultural machines capable of being moved along a direction of propagation and of cutting plants whose growth is generally vertical, has a cutter for cutting along a line making a given angle with the direction of propagation, a screw for collecting the cut stems and moving them into a flux at a given angle with the direction of propagation, and bringing them to an opening for treatment. The gear mechanism causes lateral displacement of an assembly of stems located in front of the opening and inclining the displaced stems along a direction substantially in the direction of the movement of the flux so as to send them onto the flux prior to its entry into the opening. A guide guides the flux completed by the assembly of displaced, oriented and cut stems towards the opening. The mechanism has use, in particular, for cutting cereals and forage crops intended to be treated, for example, by threshing, ensilage, etc.