a mineral concretion, usually crystals of calcium carbonate, within the epidermal cell of the leaves of some plants, (for example Urticaceae), almost always visible as light coloured spots in the leaves.
Copyright: Mike Bingham, Annette Willemen, Bart Wursten, Petra Ballings and Mark Hyde, 2011-17
Bingham, M.G., Willemen, A., Wursten, B.T., Ballings, P. and Hyde, M.A.
. Flora of Zambia: Glossary details: cystolith.
http://www.zambiaflora.com/speciesdata/glossary-display.php?glossary_id=196, retrieved 26 April 2017