An in situ and morphometric study of maize (Zea mays L.) cob rondel phytoliths from Southwestern North American landraces

•Computer-assisted morphometric analysis was applied to maize cob rondel phytoliths.•Maize glumes produce phytoliths (rondels), whereas lemmas and paleas do not.•Maize cupules are devoid of rondels, except presumably at glume attachment points.•Maize cob location affects rondel size but not shape morphometries.•Our rondel morphometries cannot discriminate between 24 indigenous maize landraces.