Taxus masonii is an extinct species of conifer in the yew family, Taxaceae,[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 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] The specific epithet masonii was chosen in honor of the botanist Herbert L. Mason, for his work with western North American fossil conifers.

[1] The seeds are identified as from a Taxus species by the exterior morphology and by the structure of the vascular supply system.