Inter Folia FRVC TVS
When I first looked at Brewer's Leigh Hunt bookplate, I noticed that there was another bookplate underneath it. I was able to lift up the Leigh Hunt bookplate from the bottom, and lo and behold, there was another Luther A. Brewer bookplate! I had no idea what INTER FOLIA FRVC TVS stood for and queried the library at the University of Iowa and received a quick and helpful reply. David Schoonover informed me that the phrase was actually Inter Folia Fructus. "Among these leaves, there is fruit" is the rough translation David provided from his memory of latin.