The concentrations of fifteen elements (B, Na, Mg, Al, P, K, Ca, Ti, Mn, Fe, Cu, Zn, Sr, Cd, Pb) in thalli of the sub-aquatic liverwort Pellia endiviifolia (Dicks .) Dum . collected from seven sites in Japan, were analyzed by inductively coupled plasma atomic emission spectrometer (ICP) . The average concentration of major essential elements in the thalli was : 49600 µg g-1 K, 9140 µg g-1 Na, 6740 µg g-1 Ca, 3840 µg g -1 P, and 3060 µg g -1 Mg . Thalli of P endiviifolia from sites polluted by heavy metals (Cu, Zn, Pb) contained high concentrations of these elements (maxima 0 .88% Cu, 0 .55% Zn and 0 .36% Pb in the older thallus), thus demonstrating the potentiality of this liverwort as an indicator for heavy metal contamination .