The character of free-convective flow near a vertical plate with a heat-flux jump on the surface is studied experimentally. Two cases of plate spatial orientation are investigated. The temperature field is measured and the velocity field is visualized in the free-convective flow near a surface. For the case of a higher heat flux from the lower portion of the plate, a change is noted in the character of the temperature profile in a boundary layer in the plate upper portion as compared with the constant heat flux surface. The shift of a temperature local maximum in a boundary layer to some distance from the surface into the flux depth is revealed. For the case of a large density of heat liberation at the initial stage of free-convective flow formation, the appearance of a two-dimensional vortex, originating from the interaction of the heated air flow with motionless cooler air in the upper portion of the plate, is found.