Dumbbell shaped grass phytoliths from Panicum sphaerocarpon.
Phytoliths are microscopic silica bodies produced by plants via the deposition of dissolved silica within or between plant cells. They are found mainly in the above ground parts of plants and are released to the environment when the plant tissue breaks down. Silica deposited in this way by biological organisms is referred to as biogenic silica or opal. Many plants incorporate silica into their structure; however, grasses are common and prolific producers of identifiable phytoliths.
Publications on phytoliths:
Fearn, M.L. 1998. Phytoliths in sediment as indicators of grass pollen source. Review of Palaeobotany and Palynology 103: 75-81.

For phytolith images and information:
University of Missouri Phytolith database
Terry Ball's Phytolith Page
Mimi Fearn Home Page
University of South Alabama
Last modified: 5/26/99