The glass, Andropogon scoparius, from two sites in northwestern Indiana was tested hydro-ponically for tolerance to zinc and copper. Plants from both sites showed a continuum of response to zinc, spanning the range of inhibition to enhancement of root growth. The urban plants were unaffected by 0.025 p.p.m. copper, whereas the rural plants were adversely affected at this level. The rural plants exhibited greater root growth than the urban plants at 0.1 p.p.m. copper. At 0.025 and 0.05 p.p.m. copper, the urban plants exhibited the greater root growth. At 0.075 and 0.l p.p.m. copper, the plants from both sites exhibited the same root growth. It was concluded that the urban site plants possess tolerance to low (0.025 p.p.m.) copper levels.