Cornus clarnensis is an extinct species of flowering plant in the dogwood family, Cornaceae,[1] solely known from the middle Eocene sediments exposed in north central Oregon.

The beds are composed of silica and calcium carbonate cemented tuffaceous sandstones, siltstones, and conglomerates which preserve either a lake delta environment, or alternatively periodic floods and volcanic mudflows preserved with hot spring activity.

The fossils were part of a group of approximately 20,000 specimens collected from 1942 to 1989 by Thomas Bones, Alonzo W. Hancock, R. A. Scott, Steven R. Manchester, and a number of high school students.

[1] In his type description Manchester noted the specific epithet clarnensis was chosen in recognition of the town of Clarno located just west of the nut beds.

The septum does not possess a central vascular bundle, indicating a placement into the Cornaceae, while the overall fruit shape confirms it is a Cornus species.