characterised by the presence of globular psilate phytoliths and vesicular infillings in the A-fraction, large globular echinate, hairbase phytoliths and anticlinal epidermal cells in the C-fraction, and tracheary elements in both. Bamboo forests are associated with bamboo short cells and the almost complete dominance of bamboo bulliforms in the C-fraction, while palm forest A-fractions are dominated by globular echinate phytoliths and have true grass percentages comparable to those from bamboo forests. Finally, fluvial forests are characterised by globular granulate, globular nodular and sclereid phytoliths in the A-fraction and Annonaceae, Asteraceae and IST phytoliths in the C-fraction, the latter two morphotypes also having high absolute (though not relative) counts in bamboo forest. The high frequencies of tracheary element phytoliths (particularly scereids, IST/(Cyl)s) in the fluvial forest is noteworthy and leads us to suggest that tree species adapted to fluvial ecosystems may deliberately produce more of these phytoliths as structural support for the xylems which have to deal with a high degree of water stress. Phytolith assemblages high in tracheary elements were similarly found to be produced by marine-adapted plants in southeast India (Kumari and Kumarasamy, 2014). Further studies of surface soils under similar fluvial forests are necessary to corroborate these findings, which could be of use to palaeoecologists tracking the extent of flooded forests in the past (Whitney et al., 2011). This study has also shown good correlations between phytolith surface soil assemblages and species inventory data, indicating that they are a result of relatively recent deposition. In the case of the fluvial forest, where we would expect alluvial transport of phytoliths to be a concern, the uniqueness of the phytolith data indicates limited mixing of phytoliths from other forest formations in the drainage basin. It is
characterised by the presence of globular psilate phytoliths and vesicular infillings in the A-fraction, large globular echinate, hairbase phytoliths and anticlinal epidermal cells in the C-fraction, and tracheary elements in both. Bamboo forests are associated with bamboo short cells and the almost complete dominance of bamboo bulliforms in the C-fraction, while palm forest A-fractions are dominated by globular echinate phytoliths and have true grass percentages comparable to those from bamboo forests. Finally, fluvial forests are characterised by globular granulate, globular nodular and sclereid phytoliths in the A-fraction and Annonaceae, Asteraceae and IST phytoliths in the C-fraction, the latter two morphotypes also having high absolute (though not relative) counts in bamboo forest. The high frequencies of tracheary element phytoliths (particularly scereids, IST/(Cyl)s) in the fluvial forest is noteworthy and leads us to suggest that tree species adapted to fluvial ecosystems may deliberately produce more of these phytoliths as structural support for the xylems which have to deal with a high degree of water stress. Phytolith assemblages high in tracheary elements were similarly found to be produced by marine-adapted plants in southeast India (Kumari and Kumarasamy, 2014). Further studies of surface soils under similar fluvial forests are necessary to corroborate these findings, which could be of use to palaeoecologists tracking the extent of flooded forests in the past (Whitney et al., 2011). This study has also shown good correlations between phytolith surface soil assemblages and species inventory data, indicating that they are a result of relatively recent deposition. In the case of the fluvial forest, where we would expect alluvial transport of phytoliths to be a concern, the uniqueness of the phytolith data indicates limited mixing of phytoliths from other forest formations in the drainage basin. It is
Watling%20et%20al%202016.docx