Paraconcavistylon is an extinct genus of flowering plant in the family Trochodendraceae comprises a single species, Paraconcavistylon wehrii. The genus is known from fossil fruits and leaves found in the early Eocene deposits of northern Washington state, United States, and southern British Columbia, Canada. The species was initially described as a member of the related extinct genus Concavistylon as "Concavistylon" wehrii, but subsequently moved to the new genus Paraconcavistylon in 2020 after additional study. Distribution and paleoenvironment Paraconcavistylon wehrii is known from specimens which were recovered from outcrops of the early Eocene, Ypresian Klondike Mountain Formation in Republic and coeval McAbee Fossil Beds near Cache Creek, British Columbia. The Klondike Mountain Formation and McAbee Fossil sites preserve upland temperate floras which were first interpreted as being microthermal, however further study has shown the floras to be more mesothermal in nature. The plant community preserved in the Klondike Mountain formation is a mixed conifer–broadleaf forest with large pollen elements of birch and golden larch, but also having notable traces of fir, spruce, cypress, and palm. Taxonomy and phylogeny The holotype was originally collected by Dwyane Day 1999 and subsequently donated to the University of Washington's Burke Museum as specimen UWBM PB 101336. One of the paratypes, specimen USNM 537360 is the earliest collected specimen, being recovered in 1901 by then Washington State Geologist Harry Landis. Study of the fossil by paleobotanists Steven Manchester et al resulted in the description of "Concavistylon" wehrii being published in 2018, 117 years after the Landis specimen was found. The specific name wehrii was chosen as a patronym honoring Wesley "Wes" Wehr for his enthusiasm and generosity. Often plant fossils are isolated parts such as leaves or seeds, which makes it difficult to identify relationships to other isolated parts. Such fossils from the same species are described as morphospecies. "Rosetta Stone" fossils are rare cases of multiple portions of a fossil preserved in connection. The holotype of Paraconcavistylon has been described as a Rosetta Stone fossil as it bears an infructescence attached to branchlet that also has leaves and terminal buds connected, allowing for a fuller plant description than is usually possible. The description of Paleocene trochodendraceous fossils from Wyoming and a phylogenetic analysis of two living and four extinct genera indicated that Concavistylon was not monophyletic. Based on the pendulous nature of "C." wehrii inflorescences, which are distinct from the erect inflorescences of C. kvacekii,