1857 R. G. Mayne (1860) Pachyphyllus, having thick leaves: pachyphyllous.
1988 Pachyphyllous, having thick leaves.
2003 www.brisrain.webcentral.com.au 26 Feb. (O.E.D. Archive) The leaves of many rainforest canopy species even in humid areas are not ‘mesophytic’ or mesomorphic, and may be coriaceous, sclerophyllous, or even ‘pachyphyllous’.