About 70 kinds of fem samples have been analyzed by means of neutron activation analysis in order to deduce characteristics and mechanisms of accumulation of rare earth elements. Accumulator species for scandium and lanthanides have been newly found based on the analysis. Correlations among barium, hafnium, and lanthanides indicate that the fems accumulating barium and hafnium also showed high concentrations of lanthanides. Remarkable accumulation of lanthanides in diversifying genera suggests that lanthanides contribute to making those species diverse.