A hyperaccumulator is a plant capable of growing in soils with very high concentrations of metals, absorbing these metals through their roots, and concentrating extremely high levels of metals in their tissues.
Rascio, Nicoletta; Navari-Izzo, Flavia (1 February 2011). "Heavy metal hyperaccumulating plants: How and why do they do it? And what makes them so interesting?". Plant Science 180 (2): 169–181. doi:10.1016/j.plantsci.2010.08.016. (ref from Wikipedia)