Correlation of phytoliths from sediments to grass taxa is a complex process, even at the subfamily level. Grass phytolith taxonomies are reviewed and compared to the phytolith content of native North Dakota grass species. Phytolith production in the species examined generally follows reported patterns; however, significant deviations occur, particularly in inflorescence material. Rondels occur abundantly in all subfamilies. Dumb-bells are not restricted to the Panicoideae, although different morphological types may correlate to specific taxa. Saddles are not restricted to the Chloridoideae. Extensive examination of modern references (both plants and natural sediments) is required for accurate interpretation of fossil phytoliths.