Phytolith sizes and assemblages differentiate genera and ecotypes of woody bamboos in subtropical Southwest China

Identifying both modern and fossil bamboos to the species and genus level is quite difficult because of the relative homogeneity of bamboo shells and their rare flowering periods. Phytolith analysis has potential taxonomic significance for identifying bamboos at the genus level. We present morphometric and assemblage analyses of phytoliths from 17 woody bamboo species within the genera Phyllostachys, Dendrocalamus and Bambusa in subtropical southwest China. The oblong concave saddle and narrow elliptates are the two most abundant phytolith morphotypes in these samples. The average lengths and widths of oblong concave saddles varied considerably between Phyllostachys (19.2 and 10.5 μm), Dendrocalamus (18.00 and 8.7 μm), and Bambusa (17.2 and 9.4 μm), suggesting that size measurements alone may be used to distinguish these genera. Further, hierarchical cluster analysis of the relative abundance of all phytolith morphotypes in these samples, as well as the morphological parameters of oblong concave saddles, demonstrate that these parameters are able to classify bamboos at the genus level. In sum, the relative abundance of specific phytolith morphotypes (narrow eliliptates and oblong concave saddles), the relative assemblages of all phytolith morphotypes, and the morphological parameters (length and width) of oblong concave saddles, all exhibit taxonomical value at the genus level for the Bambusoideae subfamily. Phytolith analysis provides an ability to taxonomically classify a culturally and ecologically significant subfamily of plants in the past and at present.