Many mosses occur both on and off serpentine soils, but experiments designed to test whether serpentine populations of widespread species display genetic adaptations for growth on serpentines have not been reported. Toward that end, two populations of the moss, Funaria flavicans, were grown on nutrient media varying in nickel and chromium concentration and in the ratio of magnesium to calcium. Three haploid siblings from each of five sporophytic families from the two populations were grown on five experimental media. There was no evidence that serpentine plants were more tolerant of nickel, chromium, high magnesium/calcium, or high nickel combined with high magnesium/calcium. In fact, plants from the nonserpentine population produced more protonemal growth than the serpentine plants on every medium except the control, on which plants from the two populations were indistinguishable. Large differences in nickel tolerance among haploid sib families (families of meiotic progeny derived from the same sporophyte) from the nonserpentine site provided evidence of genetic polymorphism in that population.