Research Projects

Plant Domestication and the Dispersal of Agriculture


«Phytolith» comes from Greek roots phyto (plant) and lithos (stone): «plant rocks». Phytoliths are plant opal silica bodies that occurred in stems, leaves, roots and inflorescence of plants.

Because phytoliths are made of silica, being arguably the more robust plant fossil, they preserve in the unfavourable conditions of preservation like the warm and humid tropics. In addition, because phytoliths decay in place, they are ideal to document what crops were planted in agricultural landscapes like raised-fields systems. Furthermore, the carbon occluded inside phytoliths can also be directly dated and in some plants phytoliths also have the added advantage that different parts of the plant produce diagnostic phytoliths, like in the case of maize. I had the privilege of learning phytolith analysis with Dolores Piperno

Nowadays, I direct the University of Exeter’s Archaeobotany and Paleoecology Laboratory, which houses a modern reference collection of more than 750 species of phytoliths and starch grains from lowland South America and I am happy to supervise student willing to learn phytolith analysis.


Iriarte, J., M. J. Power, S. Rostain, F. E. Mayle, H. Jones, J. Watling, B. S. Whitney and D. B. McKey. 2012. Fire-free land use in pre-1492 Amazonian savannas. Proceedings of the National Academy of Sciences USA 109: 6473-6478. [Open Access]

Dickau, R., M. C. Bruno, J. Iriarte, H. Prümers, C. Jaimes Betancourt, I. Holst and F. E. Mayle. 2012. Diversity of cultivars and other plant resources used at habitation sites in the Llanos de Mojos, Beni, Bolivia: evidence from macrobotanical remains, starch grains, and phytoliths. Journal of Archaeological Science 39:357-370. [Abstract]

Iriarte, J., B. Glaser, J. Watling, A. Wainwright, J. J. Birk, D. Renard, S. Rostain and D. McKey. 2010. Late Holocene Neotropical agricultural landscapes: phytolith and stable carbon isotope analysis of raised fields from French Guianan coastal savannahs. Journal of Archaeological Science 37:2984-2994. [Abstract]

Watling, J. and J. Iriarte. in press. Phytoliths from the coastal savannas of French Guiana.Quaternary International.  

Iriarte, J. and E. A. Paz. 2009. Phytolith analysis of selected native plants and modern soils from southeastern Uruguay and its implications for paleoenvironmental and archeological reconstruction. Quaternary International 193:99-123. [Abstract]

Iriarte, J. 2003.   Assessing the feasibility of identifying maize through the analysis of cross-shaped size and three-dimensional morphology of phytoliths in the grasslands of southeastern South America. Journal of Archaoelogical Science 30:1085-1094. [Abstract]

SAA Meeting 2012 – Phytolith of modern vegetations from Noel Kempff National Park – [Poster]


Piperno, D. R. 2006. Phytoliths: A Comprehensive Guide for Archaeologists and Paleoecologists. AltaMira Press, San Diego.

Pearsall, D. M. 2000. Palaeoethnobotany. A Handbook of Procedures. Academic Press. New York. 

Sandweiss, D. Small is big: The microfossil perspective on human-plant interaction. Proceedings of the National Academy of Sciences USA 104: 3021-3022. [Open Access]

Phytolith Database – University of Missouri-Columbia.

Work groups

University of Exeter
HumAnE Bioarchaeology