Acid phosphatase activity with ATP, ADP, dATP, pyrophosphate, polyphosphate, phosphoserine and phosphothreonine. Low or no activity with phosphotyrosine, AMP and phytate. a phosphate monoester + H2O = an alcohol + phosphate Binds 1 Fe cation per subunit. Binds 1 Mn(2+) ion per subunit. Optimum pH is 5-6. Homodimer. Specifically expressed in flowers. First observed in the floral apical meristem (FAP). In flowers, observed in petals and anthers, particularly in anther filaments. Belongs to the metallophosphoesterase superfamily. Purple acid phosphatase family.