Root apices, representing different types of apical tissue organization, were examined with the techniques of enzyme histochemistry. The distribution of acid phosphatase, adenosine triphosphatase, and glucose 6-phosphatase was determined for the various tissues of the root apices. Phosphatases demonstrated intense activity in the root cap, protoderm, and cortex of all the roots tested. Moderate phosphatase activity was observed in the procambial strands and differentiating tracheary elements. No activity was evident in the promeristem and root cap columella. These results are discussed with regard to the morphology of root apices, and an attempt is made to elucidate possible physiological functions in relation to enzyme localization.