From the CO2Science.org archive: Gymnocladus dioicus or Kentucky Coffee is a hardy, attractive deciduous tree that was the state tree of Kentucky until 1994 when they ditched it in favour of the Tulip Poplar. We don’t know why, as people genuinely seem to like the Kentucky coffee tree although many websites point out that the seeds are toxic when raw. As for “coffee” in keeping with the general trend to eccentricity in plant names, they can apparently be roasted and used to make a non-caffeinated coffee substitute, aka a drink that does not resemble coffee including in its effects. If however you just want to admire it for its attractive foliage, you’re in luck because a 2018 experiment showed an additional 300 ppm CO2 over 6 months increased its biomass by 15%.