A Fossil Grass (Gramineae: Chloridoideae) from the Miocene with Kranz Anatomy

Science  22 Aug 1986:
Vol. 233, Issue 4766, pp. 876-878
DOI: 10.1126/science.233.4766.876


A fossil leaf fragment collected from the Ogallala Formation of northwestern Kansas exhibits features found in taxa of the modern grass subfamily Chloridoideae. These include bullet-shaped, bicellular microhairs, dumbbell-shaped silica bodies, cross-shaped suberin cells, papillae, stomata with low dome- to triangular-shaped subsidiary cells, and Kranz leaf anatomy. The leaf fragment extends the fossil record of plants that show both anatomical and external micromorphological features indicating C4 photo-synthesis back to the Miocene. On the basis of associated mammals, the leaf fragment is assigned a Hemphillian age (7 to 5 million years ago).