Scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy, Raman spectroscopy, and X-ray diffraction were successfully used to observe the location and morphology of the silica phytoliths in biomass-derived carbons and their transformation into SiC and SiO2 particles at high heat treatment temperatures (HTT). The analyses were conducted in chars derived from the endocarp of babassu coconut (EBC), which naturally contains 1.6wt% of silica in its mineral matter. It was observed that EBC chars with 500-1200 degrees C HTT present globular echinate SiO2 phytoliths with sizes of 12-16m; these phytoliths are mostly concentrated around the surface of the submillimeter char fibers and also in the carbonaceous char matrix. No phytoliths are found in the interior of the char fibers. At 1200 degrees C HTT, the phytoliths begin to be rounded, and above 1300 degrees C HTT, most phytoliths decompose and silicon reacts with carbon-forming nanocrystalline -SiC particles (35nm crystallite size). Numerous (tens to hundreds) micro- and sub-micro-amorphous or nanostructured SiO2 particles (with sizes predominantly below 2 mu m) are then observed at the sites previously occupied by the phytoliths. Few rounded phytoliths survive at 1400 degrees C HTT, but disappear at higher HTTs (1600-2000 degrees C). It is likely that the ensembles of micro- and sub-micro-SiO2 particles observed in many sites correspond to the inner remaining part of the original phytoliths, whose most external SiO2 structures (at and near the surface) decompose and take part in the carbothermal reaction for the formation of SiC.