  We study numerically transitional coherent structures in a boundary-layer
flow with homogeneous suction at the wall (the so-called asymptotic suction
boundary layer ASBL). The dynamics restricted to the laminar-turbulent
separatrix is investigated in a spanwise-extended domain that allows for robust
localisation of all edge states. We work at fixed Reynolds number and study the
edge states as a function of the streamwise period. We demonstrate the complex
spatio-temporal dynamics of these localised states, which exhibits
multistability and undergoes complex bifurcations leading from periodic to
chaotic regimes. It is argued that in all regimes the dynamics restricted to
the edge is essentially low-dimensional and non-extensive.
