Acorns of seven sympatric species of oaks (Quercus spp.) occurring in central Florida were compared for protein-precipitating ability (PPA). Husks and cotyledons of green and ripe acoms were analyzed. Few significant differences were found between green and ripe acorns of the same species. Cotyledons were significantly higher than husks in PPA in most of the species compared. All species exhibited high intraspecific variability in PPA. Significant differences between species were found in green and ripe cotyledons and in green husks. With the exception ofQ. minima, PPA of ripe cotyledons was higher in the subgenusErythrobalanus (red oaks) than the subgenusQuercus (white oaks).