It is especially abundant in green leaves of many kinds, including grass. Because of this fact, and since we have obtained what appears to be a nearly pure chemical entity, we suggest the name folic acid (Latin, folium—leaf).
1941 August 1, Herschel K. Mitchell, Esmond E. Snell, Roger J. Williams, “The concentration of ‘folic acid’”, in Journal of the American Chemical Society, page 2284