Clones ofAgrostis gigantea,Deschampsia caespitosa,Hordeum jubatuin, andPoa compressawere evaluated for their tolerance with respect to copper, nickel, and zinc. Most of the plants originated from acidic, copper- and nickel-contaminated soils near Sudbury, Ont. Metal tolerance was assayed by measuring all of the adventitious roots growing from tillers but excluding lateral roots. Tolerance of copper, nickel, and zinc was evident in the four clones ofD.caespitosaoriginating from Sudbury. One clone ofA.giganteaoriginating from a roast bed showed tolerance of copper, while none showed tolerance of cither nickel or zinc. One clone ofP.compressafrom Sudbury indicated increased tolerance of copper and nickel, yet its root growth was inhibited at lower zinc concentrations than that of a companion clone from Sudbury and a control. TheH.jubatumplants showed no tolerance of any of the metals. Copper was most toxic to all of the species, followed by nickel and then zinc.