Backspin in does not maximize seed dispersal range, but provides moderate dispersal range that is robust to launch conditions.

is a perennial herb whose fruits explosively dehisce, launching their thin disc-like seeds over 6 m with a backspin up to 1660 Hz. While it has been previously shown that the backspin launch orientation minimizes the aerodynamic drag experienced by the seeds, it is not immediately obvious whether backspin is also the range-maximizing launch orientation. Here the three-dimensional equation of motion of a thin, spinning disc flying through a fluid medium was derived and solved numerically to simulate the flight of seeds of under different launch conditions.