Protoyucca shadishii is an extinct species of flowering plant from the family Asparagaceae, specifically within the genus Protoyucca. It is known from fossil evidence in North America, dating back to the late Cretaceous period. This plant is significant for understanding the evolutionary history of the yucca and its relatives, as it provides insights into the diversification of angiosperms during that time. The discovery of Protoyucca shadishii contributes to the broader knowledge of plant evolution and the ecological dynamics of prehistoric environments.