The phytoliths of eight genera including fifteen species of grasses under the subfamily Chloridoideae in Kerala were studied. Phytoliths were studied after chemical isolation. Every species was found to produce a diverse array of phytoliths. However the frequency assemblages of phytoliths, their size, and orientation in the epidermal layer appear to vary among the different species and hence can be used for the delimitation of the taxa. Consequently, an identification key following the International Code for Phytolith Nomenclature was developed for all the species studied.

Foliar phytolith studies were carried out in 13 genera including 29 commonly occurring species of the tribe Paniceae of the subfamily Panicoideae (Family: Poaceae) to determine the variations that exist in the phytolith characters, thereby assessing their value in identifying the species. Phytoliths were studied intact in epidermal peeling and also after isolation in acid medium. The members of the tribe were observed to produce a wide variety of lobate phytoliths including bilobate simple type, bilobate nodular, trilobate and polylobate. Ridged bilobate phytoliths produced by certain genera like Digitaria, Echinochloa and Sacciolepis are characteristic of the subfamily. Saddle shapes were not observed in any of the taxa under study. Shapes of phytoliths in the costal regions, their size, intercostal short cell silicification, nature of outer margins, presence of different appendages like papilla, microhairs, macrohairs and prickle hairs are important characters observed in epidermal peeling. Frequency percentages of different phytolith types occurring in isolated samples were also found to be reliable for taxonomic use. A key is prepared for the identification of all the 29 species studied. This could facilitate the identification of the taxa in the vegetative stage itself even when the spikelets are not available.

Phytoliths are amorphous silicon dioxide depositions in and around the cells of certain plants. Phytoliths of Poaceae are of great importance in the field of taxonomy and Archeology. Present study confirms the use of phytolith characters in the delimitation of Aristida species. Five species of Aristida were included in the study. Various characters like presence or absence of prickle hairs, nature of margins in lobate phytoliths, shank length in relation to the length of lobes etc. proved to be promising characters in the delimitation of the taxa. A taxonomic key to the identification of species is also provided.