ˈheteroˌphyllyBot. [f. as prec. + -y: in mod.F. hétérophyllie.] The condition of being heterophyllous. 1874in R. Brown Man.Bot.Gloss.1886Encycl.Brit. XX. 619/1 (Rodriguez) Variability of species and heterophylly are characteristic of the flora to quite an unusual degree.