  Guided wave dispersion is commonly assessed by Fourier analysis of the field
along a line, resulting in frequency-wavenumber dispersion curves. In
anisotropic plates, a point source can generate multiple dispersion branches
pertaining to the same modal surface, which arise due to the angle between the
power flux and the wave vector. We show that this phenomenon is particularly
pronounced near zero-group-velocity points, entailing up to six contributions
along a given direction. Stationary phase points accurately describe the
measurements conducted on a monocrystalline silicon plate.
