A concave includes a frame and an array of threshing elements supported by the frame, the threshing elements being spaced apart and extending generally parallel to one another. The threshing elements are configured in the form of round bars each having formed on an upper portion thereof disposed adjacent to an upper portion of the frame a longitudinally-extending notch respectively defining an aggressive threshing edge. The spaced apart relationship and round configuration of the threshing elements reduce plugging of the concave. The threshing edges facing in a direction opposite to the direction of crop material flow restrict crop material flow and thereby enable more effective threshing.