A mower includes a plurality of cutting units carried on a traction vehicle in a staggered and overlapped orientation to provide a cutting swath. The cutting units are rotary type cutting units having cut-outs at each front corner thereof to eliminate or reduce streaking between adjacent cutting units. In addition, each cutting unit has two spaced, ovately shaped ground engaging rollers adjacent each front corner. The ovately shaped rollers are positioned so that a tapered outer end of each roller points to the outside of the cutting unit with the broader, basal end of the roller being positioned closer to the longitudinal centerline of the cutting unit. Such rollers support the front of the cutting unit and allow the front of the cutting unit to roll over the ground.