Many studies quantify total phenolics or total tannins, but understanding the ecological role of polyphenolic
secondary metabolites requires at least an understanding of the diversity of phenolic groups
present. We used UPLC-MS/MS to measure concentrations of different polyphenol groups - including the
four most common tannin groups, the three most common flavonoid groups, and quinic acid derivatives
- in foliage from 628 eucalypts from the genera Eucalyptus, Angophora and Corymbia. We also tested for
phylogenetic signal in each of the phenolic groups. Many eucalypts contained high concentrations of
polyphenols, particularly ellagitannins, which have been relatively poorly studied, but may possess
strong oxidative activity. Because the biosynthetic pathways of many phenolic compounds share either
precursors or enzymes, we found negative correlations between the concentrations of several of the
constituents that we measured, including proanthocyanidins (PAs) and hydrolysable tannins (HTs), HTs
and flavonol derivatives, and HTs and quinic acid derivatives. We observed moderate phylogenetic signal
in all polyphenol constituents, apart from the concentration of the prodelphinidin subunit of PAs and the
mean degree of polymerisation of PAs. These two traits, which have previously been shown to be
important in determining plants' protein precipitation capacity, may have evolved under selection,
perhaps in response to climate or herbivore pressure. Hence, the signature of evolutionary history appears
to have been erased for these traits. This study is an important step in moving away from analysing
“totals” to a better understanding of how phylogenetic effects influence phenolic composition, and how
this in turn influences ecological processes.