Abstract: We studied phytoliths (plant stones) from
228 leaf samples of Guadua weberbaueri and Guadua
sarcocarpa bamboos from eleven collection locations
in Southern Peruvian Amazonia and in the state of Acre
in Brazil. Four leaf-blade transverse thin sections were
made by grinding and smoothing them into a 30 µm
thickness, and over 550 phytolith slides created by
using both the dry ashing and wet oxidation methods.
Large-sized (up to 50 µm) cuneiform bulliform cells in
the intercostal adaxial leaf-blade areas were the most
conspicuous phytoliths in Guadua leaves, but their
abundance varied even locally. Other recurrent phytolith types included bilobate, saddle, and rondel shaped
short cells; long cells in many different sizes and ornamentations; and prickle hairs, spikes, stomatal, and
inter-stomatal cells. We found the definite classification of phytoliths into morphotypes difficult because of
their variable sizes, forms, and surface characteristics.
Conjoined tricellular cell structures with one to three
mineral-accumulating cells forming a characteristic
mushroom-like constellation were also documented.
Fusoid cells forming dense rows attached to the costal
zones locally showed mineralization, indicating their
role in inorganic mineral mobilization and deposition
in Guadua leaves. Foliar phytolith assemblages showed
little variation among the different collection locations
compared to the variation found among leaves within
individual sites.

Keywords: Amazonia, bamboo, fusoid cell, Guadua,
leaf, phytolith