The percentage of tannins in leaves, bark, wood, and immature fruits of sev
eral species of Acacia and related mimosoid legumes from the southwestern U
.S. and Mexico, along with a few from Costa Rica and Argentina, was determi
ned by, a modified hide powder procedure and by precipitation with casein.
The relative percentages of hydrolyzable (Ind condensed tannins were determ
ined by, the iodate and the vanillin-HCl methods, respectively. Gallotannin
s of selected samples were also determined by, the rhodanine method. Althou
gh the amount of total tannins was similar for the first two methods, value
s for condensed tannins by, the vanillin-HCl method were frequently two to
four times greater than the total tannin values.