phytolith

From phyto- + -lith.

phytolith (plural phytoliths)

1. A small particle of silica or mineral that occurs in many plants.
   • 2016 October 29, “Sedges, not cereals, fed first settlers”, in New Scientist, number 3097, page 15:

     Environmental archaeologist Monica Ramsey, at the University of Toronto, Canada, and her colleagues studied phytoliths – microscopic silica crystals that form in plant tissues – from the site.