grasses, Tomlinsonia, California, paleoagrostology


Permineralized specimens of grasses assignable to Tomlinsonia as a new species Tomlinsonia stichkania occur in the China Ranch beds of Pliocene to possible Pleistocene age in Sperry Wash in the Alexander Hills of southeastern California. The round culm of these grasses is generally solid or occasionally hollow with collateral vascular bundles in the distinct outer and indistinct inner rings. Two-ranked leaf sheaths alternately encircle and overlap the culm. Ridges and furrows occur in the abaxial surfaces of the sheaths. The epidermis of the leaf sheaths is similar to that of the culm. The leaf lamina consists of a three-layered mesophyll. Long and short cells cannot be distinguished in the leaves, and ligules are not present. Based upon its leaf anatomy and its low ratios of -24.6%, this species is proposed as a C grass. Tomlinsonia stichkania is also important because of the rarity of permineralized grasses. It is only the second or third grass species described from specimens with this type of preservation.

Original Publication Citation

Tomlinsonia stichkania sp. nov., a permineralized grass from the Pliocene to(?) Pleistocene China Ranch beds in Sperry Wash, California. William D. Tidwell and E. M. V. Nambudiri Botanical Gazette (Chicago) (June 199), 151(2):263-274

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Peer-Reviewed Article

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The University of Chicago Press




Physical and Mathematical Sciences


Geological Sciences

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