FIG. 5. A bifurcation diagram showing grass equilibria as a
function of the grazing parameter for the system (17)-(19).If , there are three
roots. The lowest branch corresponds to the point W where , which is always a
stable equilibrium. The middle branch corresponds to the locus of
point S as
varies. Those points are unstable equilibria, so they are plotted with
a dotted line. The highest branch is the locus of point G as varies. This point is
always stable.