Darwin diagram showing the 109 transiting systems known to date with negligible obliquity and eccentricity. The total angular momentum in units of the critical angular momentum for a conservative system is plotted vs. the observed mean motion of the orbit of the planet in units of the critical mean motion. The solid line is, for a given orbit, the contribution of the orbital angular momentum to the total momentum, while the dashed line is the locus of spin-orbit synchronization. Thin dashed-three-dotted lines indicate the values L = L_c0 and n = (3 / 4)^{3 / 4}n_c0, respectively. The red domain corresponds to systems that cannot be evolving towards a stable state, whatever the efficiency of tides or AML. The purple and blue domains contain systems that could be evolving towards their stable state, while some of the systems in the blue domain could already be in their asymptotically stable orbit.