Viola guestphalica Nauenb. and Viola calaminaria (Ging.) Lej. occur in extreme habitats (on sites of very high concentrations of heavy metals in the soil) in Germany, Belgium and Holland. The calamine violets were introduced on the zinc spoil heap in Katowice - Wełnowiec in 1996, 1998 and 2001. The calamine violets were fielded in the form of small clusters (the number of the overhead tillers from ranged 6 to 13). Since then the observations and detailed biometrical measurements were conducted. The investigated taxa were proven to be good accumulators, which accumulate high doses of metals without any symptoms of their toxic effect. The calamine violets are an interesting object of ecological and physiological research. Viola calaminaria and Viola guestphalica do not belong to expansive species and they are not a threat for the native flora, but they are open to extinction due too much interest of allotment's holders, other people and demolition of the investigated zinc spoil heap.